The larger engine vs larger axle gear is pretty irrelevant, the ratio is the ratio.
http://www.ziggysmotors.com/gear_charts.htm#gearsAs for what RPM’s are better, it all depends on your motor. I have had a 160 that loved to be cranked around 5500 high with a 5200 low and would scream and one that could not catch itself if it cranked over 5100 high with a 4700 low, both obtained the SAME lap times. Each motor is different, some like to be cranked and some like to be lugged. Your motor builder will provide a dyno sheet and give a recommended RPM range.
Some also say to look at the high and some say look at the low RPM’s. I find my peak torque range and keep my low RPM’s about 200 higher than the peak torque RPM, the high is what the high is.
As for driving habits, I found that with a new driver that tends to make mistakes, getting loose and lifting off the throttle, more gear helped recover from those mistakes but if the race stayed green we were pretty much screwed, however, when there was caution after caution it was great. The better the driver gets the more you can dial the car and gear to perfection without the worry of those mistakes or your compensating of gear hurting you.
As for finding documentation, I don’t know of any other than what I have read on the forums, by talking to others and my own experience. Practice is the best way to figure out what your motor likes, go to the track with a handful of engine and axle gears and go from the extreme low to the extreme high, you may be surprised as I was with one of my motors.
And remember, just because someone tells you what gear they are running, factors like tire diameter and the engine do make a big difference between the gear on each car.