What MA said. There's no reason st all to have someone else install those kits. I've done a dozen or so of them and have never even used feeler gauges.
I have never needed the feeler guages either, but have used them once on a strictly gaming gun. My 9mm Pro CORE was a little sloppy on reset after the FSS and RAM but as it's only a range toy and I wanted every little bit I could get I tweaked it. Surely didn't need it and I was after minutia for gaming and would have ignored for ccw uses entirely.
For carry stuff the DCAEK and RAM kits have never given me a lick of problems.