Rope down the spark plug hole. I've never had a problem doing it that way. Just watch that you don't catch it in a port. You get a bit of give with the rope, so it feels weird with a wrench, but it works. I don't like using impact wrenches on cranks, unless I have no choice. Some multi cylinder 2 stroke cranks can be knocked out of time, so it's a habit I've not gotten into. Bearing mfgs say that impacts can brinell the rod bearings/races as well. Unlikely I'm sure, but again, it's something I try not to do. A few times, I've had flywheels stuck so tightly, that I had to impact the puller, but this was on large 3 cylinder PWC engines.
As for bar/chains...that saw was designed to run 3/8P chain. Don't ruin it with .325. 63PS will make it cut like a hot knife. Since you already have the 6T spur, you could just run that for now, on a new bar/chain. I run a 16" Stihl E Light bar with 63PS 55DL chain.