I carry a 1.25 Gal
No-Spill fuel can and it works great for my needs.
This little can easily fits inside one of the exterior compartments on my TC (vented to the outside of course), and I can fill up my Honda's tank without spilling a single drop. I also cary a 5 Gal No-Spill diesel can.
I'll add that I seldom run my generator, so I prefer not to have much gasoline with me....Flammable stuff ya' know ;)
Rotopax makes a really nice product and their mounting scheme is brilliant, but IMO their pour spouts leave a lot to be desired. If these fit in your budget and you have an appropriate mounting location for one (or more) then I think it's a good solution.
Cheers
-Mark