Painter--thanks for the update.
I'm still experimenting myself, so far, the 17 is still as light as I can go for 100% reliability. However, the 15 works slightly more reliably with the solid pin than it did with a broken one. I have experimented my way through 760 rounds in the last week and a half trying various combinations of ammo, firing pins, and hammer springs. I enjoyed every round, even the light hits, however.
Joe