I'll add one suggestion:
Before removing any small springs (and there are a few of them), take a break, study how the springs seem to fit together and how the part functions with the springs, and maybe even take a picture of everything. Once you take the springs out, getting them back in can be a headache because they're so small, and it can be a nightmare if you aren't absolutely sure how they're supposed to be positioned. Also, don't work over carpet.
One other thing: If you're going to a comp hammer and a SA trigger, I don't see a real need to go with a reduced power mainspring. The reduced power mainspring makes a huge difference in the DA pull, but a very minor one in the SA pull. I went back to the full power factory mainspring after converting to SA, with only a 1/16 lb difference in trigger pull weight (it went from 2 lbs to just barely - almost imperceptively - greater than 2 lbs). I think the reliability of having a heavier mainspring is a good tradeoff for an ounce or so of trigger pull weight.