hey its a bit late but based on my experience slick tires are good but regular mtb tires also work, ran about 100 miles with a mtb one before it popped, using a 45cc engine and a 1.1/8" roller
the best thing to do to get the most out of your tires is to have slow acceleration on a dry clean road. a great thing to do if you want to get into that kind of things is to make a chain reduction so you can use a larger roller, that will give the same amount of energy to your tire but over a larger area, so less stress on the tire. get some t8f sprockets and chain and some pillow block bearings, so you make a shaft for a large roller, 11t on engine and 17t or 20t on shaft, so you use a 2" or 2.1/2" roller
tried a 1.3/4" roller with no reduction on my bike, the rpm is much lower so less speed and accleration but ok for flat roads and it worked pretty good under rain and zero slipping, but yeah there is less torque from the engine so if you use a proper reduction and a 2.1/2" roller you can expect much better riding
