Just bought a 07 jk, got it for a great price. Currently running 34x10.5r17 factory gearing 4.10 is ok but looking to do the gears and a rear locker. Possibly going up to 35s eventually, and it’s a 2 door auto

 

There's a chart out there to help you pick a gear ratio but I don't have it handy. General school of thought it is that it's not worth only moving up one gear set (4.56 for you) so you'd probably be in the 4.88 or 5.13 range depending on your weight and weight of the tire. You may even be into 5.38 territory if you get on the highway and will be heavy.

 

You might actually start with verifying which axles you have. For non-rubicons in 2007, a front D44 and a rear D35 were both options instead of the normal D30/D44 combo. And as you found, 4.10's were another non-rubicon option.

Best ratio for you? Lots of variables and personal opinion involved, but my take on it is that 3.8 auto's need all the gearing they can get. Others disagree. (We all have opinions, go figure). But if you read enough reviews, you will see a theme of many people wishing they had gone higher numerically, and very few who state the opposite.

Measure your tires (not the sidewall or mfg specs, but actual measured height). It is not uncommon for 35's to measure in the 33.5-34" range...

Then do a quick google search on something like 'Jeep JK RPM Chart' or anything similar, which will bring up some colorful gearing charts that will get you in the ballpark for each ratio. From a quick glance:

3.8 auto with 34's - that measure out to 33".
4.10's = 2017 @ 70 mph
4.56's = 2243
4.88's = 2401
5.13's = 2524
5.38's = 2647

 

I have Dana 30 and 44. Just found out I can get a set of almost new 5.13 for free