hi buddy, i understand your situation as you see so many kind of meguiar's waxes on the shelf. maybe you might dont know which one to choose cause its all the same waxes.
Megs Gold Class Carnuba
natural carnuba, very wet look/high gloss, however it doesnt last long due to our weather, prefer for dark color car.

Ultimate Wax
synthetic wax, nice water beading, can apply under the sun, will last longer than carnuba, not as wet look as carnuba.

for dark color car- please note before apply this 2 product, you need to prep your surface properly as it will streak after buffing off. i have another choice for you which is OCW (Optimum Car Wax)

OCW
UV resistant, nice water beading, just spray and wipe, contains a little carnuba, will not streak on any other color, nice fragrance.