I do this often.

A few things:

-Shake it - upside down - on a regular basis. Some ingredients will have a tendency to settle on the top, shaking it upside down helps with this.

-The mixture won't be perfect and there will be hot spots. For this reason I don't add ingredients if they are going to make up less than 1% of the entire mixture, especially if it is an ingredient I don't want to overdose on. I would come up with an alternate method of using the yohimbine.

-Some ingredients don't mix too well, but you can usually get an even mixture. Ingredients that tend to clump in my experience are alpha lipoic acid, carnitine, and caffeine. My caffeine might not be any good though, I got it some time ago. If there is an ingredient that is not mixing well you will usually be able to tell by the difference in color. But, most of the time you get a good mix, herbal extracts seem to work well.