RE: T.R.U. Accelerator Balls (string)
I have used them and they the string still had a slight buzz to them.
You really need a chrono and some time to get the right spot. I have never really had a speed increase with them. But did get them to only loose 2 to 3 fps.
I think it really depends on the bow and string setup. A string without weights already on it would benifit more.