Thanks guys.
I found one that seems to fit. One down so far. The second one is being pretty stubborn, tho. Older style easy out with a square shank end that won't fit in my smaller Bosch 1/4" hex drive impact unit (great little impact for saw work, btw.) and just loosens the chuck on my 3/8" DeWalt. The Grabit or some type of 1/4" hex shank extractor may be a better way to go as I think the impact aspect is the ticket on these.
And on my SP81 rings, they're thin rings too. I see em on eBay in the $25 range. But again, I haven't found conclusive specs on end gap so don't really know how far gone mine actually are. Trying to do a compression test with a drill proved to be a fruitless exercise..., at least in my particular case. I'd go ahead and buy rings but am a little concerned about a vertical gouge in the cylinder that may render new rings moot anyway, though the piston itself is in fairly good shape and would probably benefit from them in a new cylinder somewhere down the road. Just not sure which way to go on that at this point.
I sure do appreciate the help, fellas. Thanks again.