I seriously doubt that the OP, a Solera owner, really cares about suggestions from M1 tank owners as to ways to increase fuel capacity.
The fact is, the Solera has a finite cargo capacity so any solution to extend range (with gas at 6.3 lbs per gallon) will come at a cost to cargo carrying ability.
Over the past two years I made trips of 10,400 and 5,300 miles and really never had a problem reaching a convenient fuel stop. As for stopping too much, well that's why you have a refrigerator and a nice place to relax and enjoy a quick snack.
No place to go and all day to get there!
2011 Solera 235S