I run 4.88's with 37" tires, it is a perfect combo for me and the terrain I drive on. With 34" tires I would probably go with 4.56, but I live in a mountainous area.
With your 700R4 your builder probably has his own recipe... But if you are looking for parts suggestions I would go with a Sonnax "smart shell" sunshell. It is beefier and has a Torrington bearing that eliminates thrust load on the planetary gears.
Put a .470" or .500" boost valve "V8" or Corvette sized servo in it, go with a better clutch pack, especially 3-4.
Last thing is the use of a Transgo shift kit. They have the "bootstrap" TV system that is supposed to eliminate the chance of screwing up your transmission if your TV cable breaks or isn't adjusted correctly. Fair warning, it is a totally different animal to set up the TV cable with one of the kits installed, you actually run the cable with 2-5 clicks of slack in it which you would never do otherwise.
I enjoy my 700r4. Rebuilt it at home about 3 years ago and have put 10,000 miles on it, and it gets me around on the trail and the highway.