OK, some thoughts from another big guy. I'm 6'2"/315 (I'm 69), so I get where you are coming from. That's a hell of a jump to make spending the money on that first bike, but I'm about 95% sure it'll put a huge grin on your face that won't go away for quite some time!
I learned (the hard way, as usual) that direct drive rear hubs are pretty gutless as compared to a geared rear hub. They don't like stop and go, hills, or lower speeds (say under 15mph). I have absolutely no idea why RAD has chosen to install a direct drive rear hub under what is clearly meant as a work horse.
The geared rear hubs offer MUCH more in the way of "sporty" performance. They can get you across a busy road in a much safer fashion (quickly!), do much better on hills, and still do nicely at speeds up to 20mph or so. The crazy thing is, they can do this without using much more poewer than the direct drive hubs, so battery range is not really affected as much as you would think.
My point to all this is, I think you might find the Rover a better choice. I bought a City, and started modifying it within 6 weeks of delivery. I thought it was a pig then. Today it's a completely different bike......
I wouldn't spend too much time worrying about max legal wattage either. One of the nicer things about purchasing a RAD is the fact that a fellow by the name of Bolton has taken the time and trouble to produce a kit that's able to increase the bike's performance substantially by removing factory installed electronic restrictions designed to decrease US legal performance to that legal in Canada. Highly recommended.
Last, if you go with a Rover, and ride the bike on pavement a lot, the knobs on the tires are noisey. There are tires available with a street tread that work really well, and are very quiet! Noteworthy also, is the fact these big fat tires are known to produce what might be a really back friendly ride. -Al