Make sure you support that Titan tank. Almost every Titan tank I've seen in my shop had both ends sagging. I went with a Transfer Flow tank on my 2500HD, 8 gallons less than the Titan tank(short bed), aluminized steel construction. Zero issues with it to date. Whoever the moron is at GMC that put a 26 gallon tank in a diesel truck (37 in the long beds is a liittle better) should be keel hauled.
I'm still not sure I understand all the work for the H1 wheels. Your answer seemed to indicate lots of add ons (weight), guessing that's the reason for them?
Nice truck/plans, don't see many dually's out there. It'll be fun to watch this thread.