I Just put a World Models 72" Cub together with a Magnum 80 Four Stroke. The kit's covering was very good, no wrinkel's. I used most of the hardware that came with it. Being a two piece wing I changed the attaching hardware to 6/32. ( I loose screws on the bench and at the field and don't have big supply of metric srews) It balanced out with the 80. So no added weight. Flying is fun with the 80, not scale but pull the throttle back you got scale. So I think a 90 in this set up would be fine. Dan