Wheels are easy to make, and then the cost of a 40 spoke is basically just the extra spokes. A properly built 36 spoke wheel will work, but the reality is that at our weight, we are close to tandem weights, so why the push back one always gets when the subject comes upof building a solid wheel.
Choice hub, wheelsmith straight 14s and 15s, velocity rim, brass nipples, spoke wrench. If you go that route you can come back here for the easy info on how to stress relieve the wheel for max strength.
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Amazon.com : HUB RR WM MT1110 QR SF 9sCAS 40x135 SB BK : Bike Hubs : Sports & Outdoors