Quigley conversion and fuel tankage

[Esmi2]

Guys: I PROMISE I searched the site prior to making this post, and couldn't anything appropriate. If this has been thoroughly discussed, please color me foolish and point me in the right direction...

My 1998 E350 S.O.B. Quigley conversion has a 21(ish) gallon tank. With the powerful V-10, that equates to a range of only ±225 miles. What do smart people do to carry more fuel?

It looks like UJOR's aux 35-gallon tank doesn't bolt right up under a Quigley conversion. SMB West doesn't have a solution right off the top of Peter's head.

Surely every V-10 owner wants to haul more than 225 miles worth of gas -- how do others do it?

One solution is RotoPax cans on a rack on the back. Another solution is moving the spare to a rack on the back, and installing a tank in the original spare location. What solutions are you aware of?

Thanks!