3rd dimension achieved!
With the help of a good friend the wall install went pretty well. The second wall did manage to creep a bit while we were finding square and installing the brace, but fortunately that was caught only a few screws into the install... Unscrew bump it back into place and re-screw. Did end up using PL premium and am impressed with it. I adjusted one of the braces within an hour and the wall already seemed to be self supporting with solid resistance to movement. Thanks for the suggestion guys!
Todays heat tempered my excitement a bit (humidity pushing the heat index into triple digits), but I did rummage around for the fenders and plop them on the mounts to get a look.
I sat inside and the thing does feel extremely tall. But that height is somewhat necessary in order to maneuver around comfortably on knees to the single door.
Near the top, down each side, does feel like wasted space to a certain extent. Thinking of potentially adding more storage up there. Though I am still very mindful about weight creeping in.