What do you mean by footprint? **** man, I didn't even think to check aqadvisor after getting the dimensions. I use that site a lot tooI think a standard 30 gallon tank is 36"x12"x16". 32"x12"x16" puts you at 26.6 gallons according to AqAdvisor, so actually slightly smaller volume than your 29 gallon, even though it's a couple inches longer. (29 gallon should be 30"x12"x18". Unless it's actually a 29 long, but in that case it would have a larger footprint than your new tank, not a smaller one.)
If I'm not mistaken that was a trick for the old metaframe or other slate bottomed tanks that were sealed with a tar rather than with silicone.As for the leak... I've been told, though I've never tried it myself, that putting the tank in a tub and filling both it and the tub with hot water can seal small leaks. Hopefully that'll do the trick. If not, maybe someone more experienced in tank repair can give you some other solutions.