I'd only suggest that you think about re-drilling some of the tire mounting bracket holes. If the tire can set on - or really close to - the bumper, your door hinges will last longer.
My 235/85's just squeeek onto the top of my $G rear bumper.
ed ... Oh wait. You're saying that you intend to stick a larger tire on there ... nevermind ...
That looks awesome. Besides the main tube, is that all solid steel? Also, as I'm not intimately familiar with Discos, what are the plates hanging off of the bumper for? I assume the towbar.