Hi, I have made 10x leaf with B.Caapi, Chaliponga and Damiana but after the evaporation of the menstruum
the leafs weight doubles. Is it supposed to be this way or what am I doing wrong? I'm sure that the
leaves are completely dry.

Procedure:
30g of Caapi with methanol in a jar for a month. Got the leaves out and took 3g of Caapi in the menstruum
and let it evaporate. After evaporation = 6g of Caapi.

Same procedure was done with the others. I mean, what is the purpose of 10x leaves if the leaves double their
weight and in actual case it becomes 5x leaves? Any suggestions?

Yes, it's OK. There must be some additional weight, or you would have had nothing deposited from your menstrum!
I wouldn't worry about the exact weights / ratios too much, it'll work fine.

Simply take your 6g of enhanced leaf, and make your changa with 6g of DMT. This will be pretty strong though, at 1:1 weight ratio.

When I last made Changa, I mixed the weight of the dry (or unenhanced) leaf with the same weight of DMT to give a mix of about 7g DMT: 10g enhanced leaf. 50mg of this still sends me pretty deep, with the afterglow lasting several minutes longer than DMT on its own.