Fuel tank restoration

Non Mopar so forgive me.
I have a fuel tank id think its about 10 or 12 gallons or so made out of steel for a engine drive welder (1969). I don't think I can source a new tank or even a decent used one and a aluminium replacement is very expensive, more than I want to spend
My tank has some rust on bottom, doesn't look to bad but bad enough to screw up the carb
I bought one of these 3 step restoring kits, the last step being a paint/covering type sealer
Has anyone had any luck with them on a old tank