A little more info. I just looked at the Saito 40 on Horizon's site and the weight is listed at 10.6 ounces, which you already mentioned. I figure that weight is right on. There are many people out there flying the Magic 3D with .46 size engines. An OS .46fx with a header and mousse can will weigh around 15 ounces or so, so you will be way below that weight with the Saito. It should fly great with that engine as long as it has enough power, and that's something I'm not doubting.

Wade