My 29 hit the scales last year @ 9400 lbs on the trailer with 120 gal.

Someone mentioned 500 lbs for fuel, more like 1000 lbs for a full tank.

I believe fuel is 6lb./gal.

Yup, 6 lbs/gal, so even if you full to the rim it would be 720 lbs.. :)

If you fill the 150 gal tank in the 29, you'll be at 900 lbs, unless I am missing something?

When I said mine weighed 9,400 lbs I only had 120 gal in it at the time, it holds 150 gal.