Stop being afraid of gears.
I'm running 35's and 4.88's on my 13 JK with the 6 speed and can run 60mph - 65mph and stay in the green/ECO area of the tac. My speedo is recalibrated with the AEV Procal and I'm getting the same MPG (17mpg - 17.8mpg) that I did with 3.73's and 285's (33" tire). When I was running the 285's and 3.73's, I wanted 4.10's.
You will still be in the green/ECO on your tac with 4.56's, 35's, and running 70 mph. 4.10's will not comfortably give you the full use of 6th gear especially if you do any towing/hauling or driving in the mountains.
I can guarantee 2 things.
1) You will not regret going with 4.56 gears.
2)If you go with 4.10's, you'll allways wish you chose 4.56's.
2013 Wrangler JK
2012 Wrangler JKU
2004 Wrangler TJ on LEAFS
2001 Dodge Ram 2500