Sounds like a plan.... Are you using torsion axles?I would go another inch on each side. The axle teeter totters and the tires may possibly rub the tub. Better to be safe than sorry. But I have not used an axle like that in a long time. so I could be all wet on that. I know big tires and big rocks make for a lot of movement.
Bob
The disadvantages as I see it would be top heavy trailer,more likely to tip over, and more wind resistance, The platform for the RTT would be about 6'5" tall (when extended)so if the tent was say 18 inches when folded on top of platform then total height would be about 8'. With the adjustable platform normal trailer height would be close to 4'6" or to the top of the tent(when folded) approx 6'2".Just curious, if your RTT rack was built at the full height, what do you think would be the disadvantage(s)?