So basically if you dissolve it and evaporate, of course it should stick evenly to the herbs.
BUT
if you make a too think layer - meaning too high from bottom of your glass upwards, then it will be a problem.
Why? Because Acetone is a really good solvent and your goodies will keep dissolved until the very end. If you just have 1 layer of herbs, this wont be a problem.
But if you have like 3 or more layers of herbs and they have a distinct height inside your glass, then MAYBE the point when DMT starts precipitating will be further down than your layer of herb will begin. So the highest placed herbs will not get any of your goodies ! ;(
Don't know if I described it well ... english is not my native language ... but I guess it's clear.
Always prefer a wider Jar to prevent the herbs of having multiple layers instead of a tiny jar with a herb stack.
Besides:
Herbs which have little *Hairs* can be sometimes a problem. Because those hairs tend to make Spice starting to precipitate more liekly at those points. This is just what I have seen - but this does your Spice make indeed spread not thaaaat evenly. So I got some mullein outside from the fields and this herb especially has a lot of tiny hairs and I think the spread maaaay be not that evenly.
And regarding Spice sticking to the walls of your container: This cannot be avoided and normally you would think that you are losing a lot of Spice because of this effect. But you should always make 1 measurement before + after.
Knowing the weight of Herbs + Spice + MAOI (if any) and comparing it to the Changa afterwards will make you able to check how much you lost to the container walls.
But surprisingly this is only like 10 % or even only 5 %. But just check it out to increase the number by that the next time, if you really want to achieve a certain %. And scrape the residual stuff of the walls with new herbs.