if you want to get technical, there's no specific theta rule about dangles at all-at least not in our constitution and bylaws.
Some alumnae don't wear their guard, or have connected their badges to a spouse's fraternity pin, or have removed the dangles because they're too cumbersome, or they have 'em all. Some 'upgrade' their badges. IMHO, as long as you don't overshadow the badge itself, it's entirely up to you.
My personal badge has 3 college dangles and 3 alum dangles and I'm at about the limit.
Then again, I don't wear my badge very often as I have others I like better....