3.55 = 3.54?

So I was doing a little shopping for a selectable front locker for 00 XJ (dana 30). I want a selectable so I can turn it off when I am flat towing it.
The problem I am having is that all the lockers (ARB, Eaton, OX, etc) that are selectable are either 3.54 (and down) or 3.73 (and up). Can I go with a 3.54 down and be ok?

yes

Yes 3.54 and 3.55 are the same. However, I wouldn't spend the coin on a selectable locker for 3.55 and numerically lower gears. You will spend a ton of money on it, and then whenever you are ready to regear for bigger tires, you won't be able to sell the dang thing for near what you paid for it, because people who want lockers don't usually run less than a 3.55 gear. Just my opinion though.

X2 This!

I hear what you are saying, so I'll throw another question out there. If I put an Aussie in the front, is that going to cause me problems with flat towing? (would love a trailer but no place to store it :tears
I have read conflicting reports on flat towing with a front locker.

The locker will only engage under load, so If you are in 2 wheel drive it will not engage at all because there is no load on the DS. You will only know its there in 4 wheel drive