I don't know if you have ever heard of anyone doing this, I did not read it anywhere but I got an idea when researching what I would need to diy. I ordered a peg type test tube rack and plastic test tubes with caps off ebay. The test tubes hold 5 ml, I use them for making 3 ml batches. They can't fall over when filling and when I am done mixing I put the caps on and shake them to mix them well before using the funnel to fill the bottle. I didn't want to write this down anywhere til I tried it a couple times. Then the bonus of the peg rack is I use it to dry my washed test tubes, caps, funnels and bottles. It works great for me, thought I would share it with you and see what you thought.