i doubt that the motors used in a ultralight have chrome coated cylinders
willing to bet they have castiron liners that hold the oil in the hone pattern much
better then a chromed cylinder ever could or will
comparing a rotax to a ht is like comparing a gold ingot to a cowpie
Rotax have iron liners, Hirth has nickasil, Mcculough and some others used chromed cylinders. All of these cylinders do have crosshatch.
They all seemed to like the 50-1 although some ppl did feel better with 40:1
If A high performance engine like Rotax can run nearly full throttle all it's life on 50:1, some of them reach 1200 hrs, then I see no reason why a low performance HT couldn't survive on it.
Rotax's aint that great of an engine though, Many QC problems. At the factory, the internal parts are roughly and carelessly handled after they are manufactured.
Sometimes the cranks were miss aligned, prolly from the way they would casualy toss them into bins atop the others after assembly. and inferior seals were sometimes used .Some of then would crap out at 25 to 50 hours.