I don't really know what offset my AEV Salta wheels use but I am guessing pretty close to stock. Increasing offset (pushing wheels out) puts a lot of strain on the bearings from what I understand and can lead to premature failure. I think it is wise to stick as close to stock as possible. If you were not talking about wheel offset then ignore what I just said!
I don't use offset I use backspacing and that is at 2.5" on each side, I used 2.5" spacers to make my 2 size larger than stock tires be flush with the fenders and so they don't rub on the sway bars up front or the frame when turning.
The amount of off-set or back spacing is suppose to be for centering the weight properly over your ball joints and bearings. Changing it either way can and most of the time will not only effect your handling but will unbalance the weight on your bearings. It will also exaggerate camber on turns. Keeping it within an inch of stock has very little effect on handling but add in heavier tires and rims and it can drastically effect bearing and ball joint wear.
If you needed to move your tires out or in, you should be thinking of widening or narrowing your axle. This gives you the balance you need. Most people wont do this and they just deal with the decreased life span of the parts.
Off-set is the distance from the center of the rim to the mounting flange, in or out. Back space is the distance of the rear edge to the mounting flange. A 10 inch rim with a 0 offset, the flange is centered. The same rim would have a 5 inch back space. You commonly see back-space in inchs used on American made rims and off-set in MM everywhere else.
Oh, and to answer the OP's question, I'm running 12mm of positive offset. My tire is about 1/2 inch outboard of center. This is the factory setting on mine. I'm also running an inch wider on my rim's and they don't rub.
Stock JK offset is 6.25"
AEV wheel offset is 5.3"
Most common offset used on lifted and wide tired JKs is 4.5"
Personally, I am not a fan of the super fat tire look on Jeeps, I like the tall skinny look. I have AEV Pintlers at 5.3" and 285/75/17s at about 11" wide and everything is just flush with the outside of the fenders and I have no rubbing. It took me a fair amount of research to get here, but I am super happy with the results......Others make different choices and that's totally ok, that's why Jeeps are fun.