In the past I've used ACE, and Byrons 25%. I don't think these are availible anymore. I go for SIG champion 25% and add 1-1 1/2 ozs. of caster. If I feeling wicked I use some 35% champion with added caster. If I can't use SIG I'll use some 25% generic and add caster. But at least 25% nitro.

regards - Steve B.