Spent some time today cleaning up the cylinder. Using some 400 wet/dry, ultrafine scotchbrite, and muriatic acid I got it almost perfect. There's just a hint of a score visible but it can't be felt with my fingertip of fingernail. I think it's good to go.
I even tried cleaning up the piston.
Not sure if this is still usable... that gouge between the ring and top is a pretty good one, and it still has all that pitting on the top.
I also discovered that the AM oil pump I used doesn't fit right. For starters, the o-ring is visibly thinner than the OEM one, and the boss where it sits seems shorter. I'm not sure the o-ring gets fully seated in the case. I've decided I'll reuse the OEM pump.
I gotta be honest... if I had a new ring and circlip
msp_sad
, I would have been tempted to put it all back together as is. But I'll wait for the proper parts and do it the right way.