I wouldn't use polish. Since the ball is finished with a fairly aggressive nEat pad (1500 grit), I would take an "A" pad to it to take it up to 2500 grit.

No polish is "1500" or "2500" or "3500" grit. It has the potential to be xxx grit but then all polishes have that potential. It depends on how abrasive they are, how polish you apply and how hard you press. There are a ton of human variables in addition to variable of the polish itself.

If you follow the BJI ball reviews, you'll see Joe Cerrar measures every ball with a scanner. Almost every polished ball winds up in the 5000 - 5400 grit category. So I would guess that polish is not what you want UNLESS you want a LOT more length and a more backend, in which case, the Incinerate was possibly not what you wanted in the first place.

Try an "A pad first; if that's not enough length, then try a "T" pad.

4000 w/o polish is just short of a medium polish; so it is a decent starting point.

My main point in all this is that a super oiler like this, when polished, kind of changes its whole rasion d'etre. If you tred it and it didn't work like you expected, I can understand looking for surface changes