Autoteach, that's an impressive "repair on a budget". My guess is that it will hold for many years, given your thorough prep work.
I'm renting a 1963 Willard for the summer. The owner had the tanks repaired just before I took possession. The repair involved installation of access ports, removal of sludge, and coating of the inside of the tanks. I believe that the tanks were original, based on the fact that they did not have inspection ports.
The Willard tanks had a sludge similar to the pics that Autoteacher posted. The sludge eventually stopped up a fuel line, causing one tank to stop drawing. You could clear the blockage by blowing back through the fuel line, but it would stop up again in a few hours of run time.