3.75" or 4.5" backspace?

Sorry for the newb question, folks, but there is so much to read on this subject that my mind is spinning.

I am getting ready to put my first lift on my first Jeep and I need a quick word of advice.

3" OME lift from DPGOffroad, with American Racing Mojave teflon coated wheels.

15" with a 3.75 backspace?
-or-
16" with a 4.50 backspace?

And lastly, is 31 x 10.50 the correct tire for whatever is the correct answer to that question? Bigger than that OK? Smaller than that necessary?

I am not trimming just yet.

Thanks for your time and sorry to Hasta.

Aaron

hang in there with the searching, it will really help you answer these questions for yourself!

if it were me, i would do the 15" wheel, just for price (cheaper wheels and tires) and the backspacing would look better too. 31 would probably be a good fit, however you have to ask yourself what your gunna do with the jeep?

with that lift 4.5 for sure!