I wonder it it is possible to setup a bubbleless fuel tank like the Nelson fuel tanks or not.
I think that would pretty much eliminate the risk that a fuel tank might ignite from the exhaust coming from the muffler. Plus you get to use muffler pressure too. I don't know if the plastic bag in the Nelson fuel tank is gasoline resistant or not.

Granted the risk is fairly low that one could get a fuel tank to ignite using muffler pressure. But there have been a few cases of someone getting a glow engine fuel tank to ignite when they were trying to start their glow engine. So there is some risk there in any case. Especially since gasoline is more flammable than methanol. Now we have also been using muffler pressure with model diesel engines and it hasn't been a problem, but ether is quite flammable too. But I haven't read of any reports where someone got a model diesel engine fuel tank to ignite yet.

But a bubbleless fuel tank setup might be the best way to go.