Size of heart matters more than anything.
Size of personality is next.
Size of intellect and imagination is right there.
Size of biceps is awesome (shallow...yes, at least I admit it) but in the end, size/height is relative to the first three.
I really enjoy being with a guy who is my height or slightly taller, but frankly, short guys are rare
Ideal is a REALLY big guy who is weak kneed for a shorter guy like me. THAT is perfection (of a sort...)
So, at 5'3" it's defacto going to be taller guys. How tall doesn't matter. I typically like thick, powerlifter rugby type guys - not bears so much as beefy jocks. Bodybuilders are great, but just as great are very lean hard guys. I can be more aggressive in bed with a shorter, leaner guy, but again - fun is fun if the guy is genuine, and being into each other is a must.
Genuine fun and pleasure comes from the heart.
Muscle is just a fucking prop on most guys, just like their dick, truly, and I'm bored with props. This is passion, not a magic show, and I don't care about anything as much as I do the connection.