new to seacraft have a few q's

[goodcall]

Im about to buy a 1977 20ft seacraft and i have a few quetions. 1 Fuel Cell, what size tank dose it come with, whats the biggest tank i can put in, and where can i buy them. 2 Transom, about how much dose it cost to have the whole transom replaced. 3 Stress cracks, if i replace the transom properly and have the whole boat repainted with awlgrip is it likley to see any stress cracks. 4 do you no of any good reputable places to get fiberglass work and such done around the Fl panhandle. Thanks