Cadflyer, If your engine is quiting below 1/4 throttle, It sound like your low end is two lean. I have a 2500 in a SIG Cap231, and had a similar problem. I got a ST set-up from AnnMarie Cross and the engine, as well as my other ST"S have worked flawless using her set-up. There are three adjustments, High, Low & Midrange.
WHen these are set-up right ST's run great. I posted the set-up a couple of days ago in the FUN-FLY forum. ONce you get to the FUN-FLY forum, look for the thread titled "supertigre .45 vs.". At the bottom of the first page is my post with the set-up. Give it a try. I hope it works for you like it's worked for me. Keep me posted in your progress.

Kcflyer