In that case, I'd strongly advise anyone doing the same, to have enough fuel to cover 800km and some. If that means you have to lug 80L in jerry cans, so be it, because in such situations you cannot assume that those gas stations even have fuel, or it could be closed for the weekend. It would seriously suck to be stuck there for a few days because you do not have more fuel.
You are right. I'd advise myself to do that now. That journey happened 20 years ago so I don't remember the details. Maybe we did have some cans or maybe we were just fools used to the gas stations of Europe's highways.
