M4ssboss3 is very unbalanced compared to Xmax. It also has a lot more heroes/champions in groups of 3 to deal with as well as mob size increases. When I tried it as a new toon right from the start I ran into three groups just over the bridge in Helos which killed me a couple of times before I lured them to the guards to help deal with them. Bosses also spawn in groups of 24. Yeah, that figure's right - 24 of each including the Gorgon Sisters which means you fight 72 of them!
M4ssboss3 is more for farming only, rather than playing from the beginning to end. It's a little better in Act 4 when they're reduced to 12 of each.
Quique wrote a guide a while back which gives a bit more info.
https://titanquestfans.net/index.php?topic=704.msg7233#newI did have a journal for the Diviner I tried this mod out with back on the old forum. Don't have all of it, but this is the beginning of it which hopefully will give you some indication.
"Let me start by saying this is a big leap in playing the game for me. I've only recently started playing the full version of Xmax and this is way more difficult so be warned if you want to try it.
As the title says I'm playing a Diviner (Spirit/Dream) and using much of the advice and gear recommendations in Poinas' excellent Pwning with Spirit guide although I won't be taking the strength route except to get enough to be able to equip Stonebinder's Cuffs. I'm also a) using items from my Vault collection and b) playing with the "Relics/Charms in Uniques" mod which is available in the Defiler program. This is how I usually play TQIT anyway and for this mod I think I'll really need all the help I can get!
Let's get started. Having made my character I first exited the game then used the mods in Defiler to a) make all the inventory bags available and b) expand the personal storage area of the caravan. Once those were done I gave her a set of white and yellow items from the Vault plus most importantly LOTS of health potions and got started.
First big surprise - like the Achilles mod this one also has heroes spawning all over the place. I ran into Caldor Darkbow, Marnos Rockbiter and Algos Frostwind in multiple forms just past the bridge and died twice trying to deal with them all because I wasn't expecting them.
What eventually worked for me at L2/3 seeing that she only had Deathchill Aura with a point in was to lure the heroes to the guards at the bridge. The heroes focussed on them and of course the guards can't be killed because it's not written in the game that they can be. So they won't die no matter how long it takes for your toon to bring them down. I was able to pick off Caldor Darkbow x2 from the bridge with ranged staff attacks and got the third when I levelled up to L4 and got a point into Ternion.
The 3 Marnos Rockbiters were the worst because even trying to fight them using Ternion close in they just kept reducing my health and I had to run around a lot while I downed potions and waited for the health bar to recover. Eventually I headed back to the village entrance and the guards there distracted them so I was able to use the same ranged attack idea as I had on Caldor. This tactic should work for any ranged/caster toon.
Algos Frostwind was easy to deal with as he can be picked off from a distance.
By this point she'd levelled up to L4/5 so I had some points in Spirit plus a point in Deathchill Aura and also Ternion Attack. She was also able to equip the yellow items which also helped. She worked her way through the various mobs and eventually cleared nearly all the ones hanging around the Satyr Shaman area as well. Then she was ready to go after them. They turned out to be quite easy as she was able to take them on one by one so wasn't in any danger of dying.
That was where I had to leave the session, but she was up to L7 and had the following gear:
Hood of the Magi of Stability socketed with Boar Hide (+DA bonus)
Hardened Padded Silk Mantle of Recovery socketed with Essence of the Golden Fleece (elemental resistance bonus)
Hardened Bronze Bracelet of Recovery socketed with Pristine Plumage (+DA bonus)
Hardened Embroidered Linen Wraps of Rejuvenation socketed with Essence of Hermes' Sandals (+DA bonus)
Storm Eye socketed with Essence of Hecate's Crescent (elemental resistance bonus)
Protective Gold Loop of Energy Cold resistance socketed with Demon's Blood (vitality damage resistance bonus)
Protective Bronze Beads of Energy Lightning Resistance
Tainted Staff of the Magi in first weapon slot, Sanguine Staff of the Magi second slot - both socketed with Essence of Prometheus' Flame (fire damage bonus)
Next up it was time to head down the road for Sparta. Once again Caldow Darkbow, Marnos Rockbiter and Algos Frostwind all made an appearance around the satyr camps, as did Fernos Charskin but attacking and kiting and downing health potions kept her alive.
No real problems in the Shepherd's Cave, but in the next section ran into Aello, the Talon of the Storm. By this point she was up to L8 and I had added Dream into the mix to give me Psionic Touch as a boost to normal staff fire and Distortion Wave as a slowing agent.
The run up to the Missing Necklace side quest was just mobs and mobs of foes, no heroes to deal with, but in the cave I ran into Black Bite and Goat Sucker but they didn't present any problems.
Getting to the fountain before Sparta was the end of another session.
Working through the Sparta camp areas was again not too difficult. Heroes met along the way were Panos, Lord of the Briarwood, Sildor Barb Net, Skiron Emberwood and Sergos Longstride. Unfortunately when I got to Nessus they weren't there. This does happen with mods like Xmax so I exited the game and re-ran the area and they were there this time. Firing off Ternion and then retreating allowed me to bring them down bit by bit until all 24 were dead.
Continued on through the Spartan Woods and down to the Mycenean Ruins where I met up with Rot Bone, Cinder Bone and Graklos the Graveless. Ternion is really proving to be a great skill for this mod both in tackling the mobs long distance and for downing heroes close in. Time to end the session with Averil up to L15. She has a Brimstone ring equipped now and also a Therguist's necklace. Plus she's now wearing the Oracle set except for the bracelets which I've swapped out for some Ceremonial Bracers of Recovery. I'll push her strength up a little more so as to equip some Stonebinder's over the next few levels. I'm also working on maxing out Deathchill Aura and climbing up Dream to get to Trance of Convalescence."
Can't remember what level she got up to now, but she had reached Act 4 Normal - and she yes died a fair few times along the way. That doesn't worry me, I'm not a hardcore player and all my toons suffer death sooner or later. I still have her backed up and might get around to continuing with her if the mod gets updated for AER.