Since you currently have 3.69's I assume you also have a manual transmission. Which means at highway speeds (120 km / hour) your current RPM's with 3.69's and 33" tires should be about 2200 - 2500 give or take. Running 35's and 4.56's you'll likely be in the 2500 to 2800 RPM range.
For what it's worth, my good friend just installed 4.56's in his manual Frontier and he is only running 33"s.