At least you have options now right! I'm not sure what I would do personally since they both have some advantages. The 11:00x20's dualled up on stock wheels would be nice for the spare issue. I like the look of the dualled 11:00x20 a lot also, but I also like the look of matching truck and trailer wheels.
I guess I can only offer a little insight on those MRAP wheels you have. On my 109 camper conversion, I singled it out and put on the same MRAP wheels you have. In order to get the tire to sit somewhat flat on the ground, I had to drop air pressure down to about 35psi (I assume it would be higher for your trailer). This gives the truck a really nice ride since it adds a bit of "suspension" over what the duals offered. However when we are walking around inside the camper now, the truck isn't as stable so we can feel it moving more when parked due to the "suspension" of the 395 tires. So in a nut shell:when using super singles the trailer won't be as stable when moving about in it, but it will be nicer ride (if that even matters?).
I also dont know much about the m146 hubs, even if you could flip them I dont think you would want to. If you went with the super single MRAPs, you would just want to mount them dish side out which is how they are mounted on the BUFFALO MRAP (see pic below) and I assume how your singles are mounted to your m932A2. The valve stem wont be facing out, but should still very easy to get to. Your MRAPs do have a runflat in them incase you somehow puncture one by chance. Also since there is no gearing issues with a trailer axle, you could always just bring a stock spare or 1100 spare on stock rim with. You can probably buy a deuce spare tire mount/winch and figure out a way to mount it to the trailer frame..... Either way, post some pics of it all when you get it done!