despite common beliefs.....
you shouldn't try to restrict yourself to having a 45ci if your front, 68 if your mid or 88 if your back. But instead go for whatever bottle feels most comfortable, as then you will be able to play "better" as you wont have to worry about your bottle slipping off your shoulder, snagging under your arm or your gun hitting you in the nose when you tuck in.
P.S. Just a passing thought, whatever rail/drop forward/unimount ect. you happen to be using can make everything feel alot different, so best bear that in mind if your trying out diffent bottles.