Hey-ho, I thought I'd share the statistics i gathered last year from maze running. The idea is: with a suitable build put on all the items you'd like cloned, get the fountain at Mimer's maze, check all the places where the doppel can spawn (except for one, you can see on the map below, it's counterproductive to run there), reload the game, repeat 2644 times. 2644? Well there was more, but thats how many i have taken notes of, then kinda stopped ^^;
By "suitable build", it would preferably be a toon which can wear all types of items, depending on what you're after of course, and can still survive without the original gear. Petmancers are highly effective in that. I find the good ol' pet-champion perfect for the job. The only use I have out of her.
The items that can be cloned are not limited to the rarity level, but you can't drop artifacts, rings, or amulets - the bonuses from them don't apply to the doppelganger hero either. I'm fairly positive that both weapon slots are counted as one, I have merged them together, because I would sometimes use a bow or a staff, yet the drop number of weapons and shields is equal to that of each armor slot.
Why would you need multiples of the same item?:
1) It makes life easier, when you use the same one on multiple characters, so you don't need to transfer
2) Trading / sharing copies of upgraded items
3) Re-rolling the stats on an item
All the runs were done with vanilla TQ. Using 6-players difficulty can be more efficient, and the maximum amount of doppels in one run is increased (dunno the limit though)
Item drop statistics from runs 1-1000:
Item drop statistics from runs 1001-2000:
With each run there's around a 43,1% chance for at least 1 doppelganger:
31,6% - 1 doppel in the maze
9,9% - 2 doppels
1,2% - 3 doppels
0,4% - 4 doppels
Each one of them has that 10-11% chance to drop an item, so technically you could get 4 items from just one run, the most i ever got were 2 though :p
The path to take:
You can see through the wall the last chamber, so if there's only one phantasm there, a dopply will spawn, or perhaps it pre-spawned, either way, if there are 2 phantasms you don't need to run there.
Quick note, if the chest in the middle of the maze is locked, the doppel has spawned in the area to the right, where I usually don't check, so that's the one exception for when I would run there.
Here's a quick video of an example run, slap on all the desired items, making sure the movement speed is high, and there's some -recharge in there in my champion's case, and teleport around with war wind.
Hope this was informative to some of you :>