I believe your problems will be cured with what you've ordered already.
The small amount of lapping which cylinder throat get is not much of a factor in performance, as they only get one bullet per hole for each 6 down the barrel. Best way to get them to proper size is to polish per the lap instructions using a sized bullet as a guide. Cylinders should be enlarged, if they need it, before lapping the barrel, because if they are undersize they will size the lap bullet smaller than bore, which will prevent it from reaching groove diameter of the barre.
45 pistol push through slugs will work for all 45 pistol chamberings, so you can slug both the Sig and the revolver. I'm quite certain that lapping will cure the Sig permanently. Pay attention to how the push through slug slides through and see if there is a tight spot just before the area that leads, or if that area is tight or loose. Do a push through again after lapping to be sure you fixed the problem. The instructions with come with both the lap kit and the push throughs are very complete, so you'll be an expert on bores when you are done. Be sure to post your results here, please, even if it puts egg on my face! Actually it won't, because leading always has a cause, though it is sometimes a bit hard to figure out from a distence.
I'll do whatever it takes to get you happy with performance.
