Here (and I'm in a fairly small area), 25 is a pretty sweet spot age wise. Wait until you are 40 and see all the ads "...blah blah blah, no one over 35". As for body type, there seems to be more interest in dick size than anything else, which is sad. My arm is bigger than any dick, so there! lol seriously tho, I dont know what to tell you. I do prefer men that are somewhat like me physically, tho I know of guys old enough to be my dad who are interested only in guys young enough to be my son. there seems to be a lot of racial exclusion as well here.
Just a guess here, but a big guy might not like a little guy because the little guy makes him self conscious (unless the bigger guy is muscular)?
I know that although I dont have a particular body type, effeminate (especially, an forgive if this is the wrong term, "flamer" type) guys dont do it for me at all, tho that may because I'm bi, but I also dont like super girly women either.
Not to derail OP's topic, but what are "cubs"? Is this younger/smaller/less hairy "bears", or am I barking up the wrong tree?