I think the 46 will fly ok with the SX50. I had that engine on an Ultra Stick 40 and liked it ok. It's no 4 stroke but it's a good engine. I think the lighter you keep the plane the better it will fly. I'm not sure the vertical would be unlimited but I do think it would hover with some pull out. I'd save some money and buy the first Saito 82 you can find. You'd be amazed at what this plane will do with that engine.

Thanks
Barry