Thanks for the advice guys, and no worries, I'm hard to scare off.
I'll start with 20 grains, I've got FFG Goex that I can use, and some old Elephant brand someplace, I think that can's FG
I'll use a rope to control the recoil I think, seems like a good idea, and had kinda thought about that with the light carriage anyways.
I might even get to shoot it this week, we'll see.
Thanks again