I have zero experience with those wheels, but if I was riding at 390 lbs I'd be looking for wheels like that. At my highest weight ever I was 380 lbs, but by the time I started riding my mountain bike I was around 360-365 or so, and in the first few days of riding it I popped a couple spokes just riding off a curb while firmly seated in the saddle (so my whole weight came to bear on the wheel in an instant). If I'd stood up from the saddle I could probably have ridden off the curb without popping spokes, but that experience definitely gives me a certain attitude towards riding at those higher weights. I've read posts from folks who claimed to have weighed similar weights and rode wheels for years with low spoke counts just fine. Good for them. I wouldn't do it.
I'm in the 270s right now and my tough road bike wheelset has 36 spokes both front and rear for toughness and durability. In fairness, I'm building a new front wheel that will only use 28 spokes, but I have no plans to drop from 36 spokes in the rear at least until I'm in the very low 200s.