There's a profile bird called a Hyper Active that might be a good match for the 91 FX at your altitude. Should be able to come in right around 5 pounds, which is 8 to 12 ounces lighter than the MoJo 60, with a good bit more wing area than a MoJo 40. The problem is that kits are very hard to find. It's kitted by the guy who designed it and he does small production runs which are usually sold out as soon as he announces that he's doing a run. If you poke around a bit on the profile brotherhood site, I'm sure you can find out how soon they might be available.....or perhaps find someone will to part with a kit. Here's a couple of pics of one built by a legendary Bro.