Very interesting experiment. I only have a suggestion to take out one source of systematic error. Use one and only one razor, and do the different experiments sequentially. Also, prepare the blade by honing exactly the same each time. When you are finished with, say two weeks of doing the "30 passes before" experiment, then switch to the scheme of doing "30 before and 30 after", etc. In my very limited opinion, the hardness of the steel may not be that easy to control during manufacture. Especially if the guys making the TIs are really dipping them by hand into molten lead and quenching them in oil (I read that somewhere, maybe the classicshaving.com website). I suspect the variability of that process may produce blades of slightly differing hardness that could affect the results of your study.

E