I went back to the beginning of this thread and looked at the pics of the valves and valve seats. I am curious as to why you would have a wide valve clearance. Normally as an engine gets older the clearances get small, not larger. I would be double checking those measurements as I don’t see a reason that those measurements should be so large. Second, to get the clearance back into specs you are going have to cut the valve seats and then grind the valve faces. If the valve margin becomes less that 3/32”, the valve will not have enough thickness to deal with the heat and fail very quickly. If you do get the clearance in specs, you then have to lap the valves. Here you must make sure that the lapped surface is in the middle of the valve face or the valve will not seat properly, causing a loss of compression. Have you checked valve guide clearance? If the clearance is too large, all your work on the valves and seat will be for naught. Finally, are you sure you really want to stick the time and money into that engine? You have a scored cylinder, bad rings, probably a worn piston due to piston slap, could be replacing valves and will need a gasket set. Plus if you do just the bare minimum it may not last a season. Personally, from the pictures you posted and the measurements you gave us, I would tell you to stop now and cut your loses. Read my signature.