Either one of these should hit pretty hard and do so with out blowing out a huge hole. At that range ballistics is irrelevant. The lead should expand/deform a little bit more than the solid so it has the potential of making a bigger hole, but I wouldn't expect it to create as much damage as a bullet designed for expansion.
Not trying to stir the pot but there's evidence to say that a solid bullet that doesn't expand has the potential to be less lethal with less-than-perfect hits than an expanding bullet. Something else to consider.
Another, cheaper option would be surplus military ball ammo. By international law it has to be non-expanding and should leave a clean in/out hole. I'd be more partial to the round/flat nose myself when dealing with a gator that close, but up here in Montana we don't have much call for dispatching gators so Ican't claim much experience