Fuel Tank replacement

[cooppat]

After filling the tank for the 1st time on my 74 20' sf, I discovered a fuel leak. I removed the fuel tank panel and found a saturated fuel cavity. The leak was on the port side of the tank just below the rear mounting bracket. the tank was in rough shape. Prior to filling the tank I drained the old fuel and filled it with 40 gallons of new fuel, determining that I had a 40 gallon tank. I have read several posts about the tank removal and replacement all very helpful. I have the tank removed and I have included several photos of the old tank and tank compartment. The tank was mounted to the side of the stringers with some rubber pads at the brackets, and the bootom of the tank had some rubber tapping material attached to it, and the sides were sorrounded by foam. The tank measures 24" x 60" x 8". The tank is flat and was resting on a flat fiberglass coated board, I have not removed this board yet. I am going to remove all the old foam on the sides, and clean up the area, and replace the fill hose and main fuel line.


My questions are the folllowing:

Is this the orginal tank?
What should I replace it with? I was hoping for 55gal
Should I remove the board?
Should I coat the tank?
Should it be foamed back in, from the posts I have read it sounds like I shouldn't.
How should I attach the new tank?

I hope these pictures are helpful.

http://img.photobucket.com/albums/v6...ankareaaft.jpg
http://img.photobucket.com/albums/v6...ankforward.jpg
http://img.photobucket.com/albums/v6...laftatleak.jpg
http://img.photobucket.com/albums/v6...tankbottom.jpg
http://img.photobucket.com/albums/v6...idebracket.jpg
http://img.photobucket.com/albums/v6...eedandvent.jpg