stupid questionq

ok so i have a 97 ranger, and i'm looking to get a optima battery. i'm going to be running 2 compressors, and thats it as far as major electrical shit. my question is should i get a red or a yellow top. and also do these batteries have diffrent sizes like regular batts, or is it just one size. i know its stupid but i have diffrent ppl telling me diffrent things. any help would be swell-alex