That looks like an older recipie where 5% BA was common and I think BB was harder to get and not often used. I guess those longer esters are relatively easier to hold without crashing, and BA is a solvent so some hormones will hold in just BA, but BB is a better solvent where some BA is still needed since it serves the purpose of sterilizing the solution (1 % is enough to kill the bacteria; 2% is a good safe number to use for BA). If you make it without BB and it crashes just heat it up until the crystals dissolve and add some BB, and just keep track and do the math to figure out your mg/mL. You don't want to use stuff that crashes easy even if you don't mind lightly heating it before every use, since if it crashes in your body it's going to hurt having those crystals in a depot of oil. I think it's easier to just use 2/20 in every normal concentration brew. Test is fine to heat; melting point is 98-102C for cypionate so just keep it well below that when heating and take it out as soon as it dissolves, otherwise if you leave it in the oven for a while you'll have to vent it and then worry about loosing the BA to evaporation.
