hi everyone..
a few months back i bought a ball python that i fell in love with and is very healthy and eating well.. and recently ive been thinking about getting a red tail boa and i just wanted to know a few answers to some newbie type questions..

i have a 20gal. long glass aquarium (critter cage) with a sliding top, approx. how long is appropriate for a boa to live in it before upgrading to a bigger size? how big should he/she be before upgrading?

i know ball pythons are picky eaters, mine however is not sometimes she eats 2 mice in one sitting with no problems and has never rejected a meal.... are boas picky eaters? do they ever reject meals.... (even though i would never do this) i heard of morons feeding mouse after mouse...or rat after rat just to watch them eat because it was "cool"... is this even possible?... is it possible to over feed a boa or like a bp will they just stop when theyre full?...

and last question which pretty much relates to my first one..

whats the absolute biggest size tank i would have to get for my snake?... im prepared to spend whatever it takes i would just like to know ahead of time what im getting into..

thanks.