Not very long. XD It isn't going to stay 3-4 inches long for a few months.
Okay, seriously, now, I believe it'll be fine for a few months as long as the tank is twice as long as the aro and there plenty of room to turn around.
I say you dont even get a silver aro. you said youre not even sure if you will get a 300g. if you dont get it, then what? the silver aro is gonna die in your 110?