The main issue with a tapered bore is that the rings expand and contract as they go up and down the cylinder, take a piece of wire and bend it enough times and it breaks, the taper does not really affect sealing all that much unless super excessive. Ring breakage is what you need to worry about. And 90% of the wear will be in the top inch of the bore, so majority of the cylinder will be straight. I used to fix a lot of farmer overhauls back when I was young, where they just run a hone and installed rings, I used to pull the pistons out and just shake off the rings. I would use just a normal ductile iron moly face ring on a couple thousands taper. What I do is run a rigid hone down the bore a few strokes and all the wear spots in the cylinder will be easy to see and measure, out of round is what keeps rings from sealing, again easy to see and measure if you use a good rigid hone first. My quick and dirty rule is, if you can catch a ridge with your fingernail at the top of the bore, it needs to be bored.