That amount of carbon is nowhere near normal. I strongly recommend taking the cylinder with piston, and the head assembly to a good machine shop. I know you want to do it yourself, but there is more hear than meets the eye. Problems I've run into are :
Seizures that distort the cylinder so badly that no amount of honing will allow new rings to seat. You probably need a bore job with new piston and rings. This could be the cause of the oiling/carbon build up.
Worn out or dropped valve guides. Last year I had a customer with a dropped
guide. It allowed a lot of oil into the combustion chamber. There was a lot of
carbon.
Rod damage caused by seizure.
All of these conditions require special tooling to even get to and measure. Do you have a bore gauge, a valve spring compressor, and valve seat cutters in the proper angle? And specialized knowledge to properly interpret what you are looking at? The tear down and reassemble is straight forward. I certainly encourage your efforts, but these kind of projects are not fun if you have to repeat them. A machine shop would be the difference between a 1,000 mile or a 20,000 rebuild. I would be happy to talk you through some of this stuff. Call me toll free at I 866-VINCEMC. I'm here 10 to 6 Pacific time Tues - Sat.