OP - Go have some fun:)! The T-125 will give you just a tad more AH's available then the T-105's. (240AH vs 225AH for about .066% more juice.).
Our first 'used' Bounder, had two mixed GC batteries - both were bulging. Still remember the 1st owner commenting 'Well, those batteries might need a look at.':)! Only had room for X's GC2 batteries. Wanted to fit the T-145's, but just not enough head room. So, X's 2 T-125's went in.
I sold that Bounder to a neighbor 6 years later. He replaced that set at age 10, because he thought he should:)! Due to very poor access to the top, I added the the turkey baster squeeze ball watering system. KISS it was. About once a month I'd go squeeze the ball until firm, usually not even a full squeeze was required. Very seldom did it ever require a partial second squeeze. (That's battery water techie talk, to say in our application they did not consume much water:)!).
Have a good trip:)!
Smitty