Something to match the 395 in height? (taller than the G177)
1. I have seen dualled 12:00 tires on a deuce, but years ago and I think they were an old bias ply tire. They definitely weren't a
"modern" tire lie an XL, T831 or G177.
2. I have a set of dualled G177s on my deuce and I can almost guarantee you won't get anything larger on the truck dualled. The inner tires are so close to the trunnion that several members have had issues with the tires rubbing on the bolts of the dust cover.
3. My 177s stick out just a hair out from under the bed. I think a 12:00 would be a bit worse and just cosmetically, I don't care for it.
4. You won't be able to run a spare on the stock spare tire carrier. Maybe if you modify it or get an M35A3 carrier it would work, the M35A3 has 14:50R20 tires and it has a spare.

5. Goodyear says an 11:00R20 G177 is 43.3" (
http://www.goodyear.ca/cfmx/web/truckca/line.cfm?prodline=161006), a 12:00R20 G177 is 44.7" (
https://www.goodyear.com/cfmx/web/gov/pdf/military_tire_brochure.pdf) and a 395/80R20 is 46.6" (see brochure pdf). So you're already pretty close.
Other pics.









