Holy shite Gilly!
20ml of BA. Can you say ouch.
I made 100ml of 100mg/ml prop with zero pain using 6-8% BA and 10-12% BB. The BB is painless in comparison to the BA. You might want to think about lowering the BA and substituting with BB. Also, I like to heat up the solution after disolving the powder at 200-250 degree for at least a half hour. It makes the filter much easier and helps to sterilize it.
MH