+1 on availability of the quart cans. I tend to find them more at independent camping stores and at REI and EMS. Only once was I low and forced to buy a gallon. I left behind at a campground what I could not carry for others to use. And I also had a camp store offer to fill my fuel bottle from a gallon can. If you don't want to carry two fuel bottles, you can simply carry the can with the remaining fuel in your pannier and top off your bottle each time you use the stove until the can is empty.
In places where I have stopped to look for fuel on tour I took notice of what white gas was available despite the fact that I was using alcohol or butane. My impression was that quarts are becoming more common, but still not all that widely available.
Also at least for me I think that a quart is an awful lot to carry at one time any way, Given that I find 12 ounces about right for alcohol and that alcohol has quite a bit fewer BTUs per volume, a quart of white gas would last me a very long time. A pint would be more acceptable, but IMO even that might be a bit larger than optimum.