The reason they use unf or unc is when you have multiple thread pitches for the same size fastener.
IE 10-32 would be UNF, fine thread.
10-24 would be UNC, coarse thread.
Update for ya gents, I just ordered some blanks and .028IFRs. Going to tweak one thing at a time. Well I guess two in this case. Blocking the middle emulsion holes, and removing the top .031 IFR and replacing it with a .028 on the bottom as Turk recommended.
I cant get any brass set screws locally and soonest I can ship any is next week, winter storm surely not helping, so t-slot restrictors will come later.
I do have a question that may have been answered but I'm half asleep and wrapping up my thoughts: is the pump shot an entirely independent circuit? As in the changes I'm making won't affect the stumble if the pump shot was an issue?