I'd respectfully disagree that 4.88's being "too much". I initially had 255/85/16 SS TrXus tires when I regeared with 4.88's, having it done @Inchworm before I did Rubithon '08, then drove home to NC. Knowing this, I took very careful MPG measurements to CA and back to NC.
Strangely enough, I got better MPG's on the way home, not by a great deal but it was better. I put 35's on within a month of being home and MPG dropped through the floor with the nice, light and nimble Swamper SSR's.
I attributed the gain in MPG's as "driving downhill and with the wind", coming from CA to NC but all other things were the same, passengers, load, everything.
My last FJCS (5), I openly allowed anyone who called me out in the "blue room" for my statements how valued I felt regearing is if one is driving around on 35's, stating that it "didn't make that much difference" and "there is no need to regear". Nothing better to see their face and hear their comments after we got out of my 4.88 geared FJC.
In any event, I'd go at least 4.56's but know that one won't regret going with 4.88's IMHO...