http://www.steelsoldiers.com/showthread.php?28757-Tire-Size-Difference
I used the Webster's meaning for "about" - reasonably close to.
Meaning, IMHO, if he were to use a setup close to mine, I feel he would achieve nearly the same results and the small differences in tire size would not adversely impact performance of the mission.
The sizes listed in the chart I posted are a good starting point, but you also have to factor in tire pressure, wear and manufacture. Using a tape measure and a level my sample tire installed on the rear of my truck measures 43 1/4 inches. I don't have a 395 to check.