You wrote you tried the accel pump screw. did you take the air cleaner off to observe how big a shot it pumped into the throat? Not when running, just to see.

 

.023 on the slow jet seems a bit small. 0.295 is usually about average. I run a 295 and a 71 on my 93 FLSTC with slightly more than 1 1/2 turns on on the pump and throttle response is fine. Also, if your idle is below 950 you'll have problems with throttle response on a quick twist.

 

Run Vance and Hines Long Shots got a 28/72....top end is awesome. At idle it eratic. I get it set then it will change on me when im riding . Sometimes it acts it going to die on me at stop sign or sometimes it will idiling faster