I'm about to build a custom fuel tank that will mostly use auto fuel. Ethanol free fuel is available, but still is a concern. Of course a welded aluminum tank would be ideal, and still possible, but a composite tank would be easier (and cheaper) for me. Lancairs,etc use a Jeffco sealer (expensive) but I don't need the amount sold by Aircraft Spruce (3gal.) so my question is, would it be possible/prudent to "skin" the entire inside of my composite 22 gallon tank with Proseal as is used on the seams of RV tanks? This would appear to be a cheaper alternative to the Jeffco option.