Lot of things going on here that aren't optimal. The other part of the equation is low budget. Dykes rings dont grow on trees. Macining the piston for different rings is a very precise machining operation. Cylinder walls aren't great and probably aren't straight. My take? Hit it with a ball hone and put it back together. It is what it is. It'll run fine. Make optimal power, no.
I'll bet there are thousands of bracket race engines that aren't any better.
Doug