My outlook is, if you're handy with tools but not rich, many things are better done yourself. To properly de-rust a gas tank, you nearly always must remove it... and the tank only comes out after both the engine and transaxle are laying on the ground. At that point, you can assess the problem better and do as you described. You trade money for grunt-labor here. The Nor-Cal club experts did this for free on an incapacitated members' car one Saturday- 6 of us started at 10AM and the owner took the completed car around the block at 5:30 that afternoon... His job was to keep the beer cold and the Chili hot- an even trade.
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