While I know the emulsions are going to have various characteristic curves (Ilford SFX being my best bet for a panchromatic film that's known to be IR sensitive, down to say Arista EDU Ultra/Foma 200 that isn't listed as having it, but can create a wood effect when exposed as IE 6).
I tested my R72 on my little Pentax Q10, which I haven't tried the R72 filter on before so I don't know how sensitive it is compared to my Olympus E-M5 (I know my Panasonic GH1 is less sensitive than the E-M5, so much so it's impractical to use for it). Course this is off of some CFLs in the house, both my ceiling lights and desk lamp are using 100W equivalent, 6500K balanced CFLs, so actual daylight infrared could be stronger.
A metered exposure at 30 seconds, f/2, ISO 400 with the Hoya R72 filter on front.
Then reduced the shutter until it showed the same metered results, everything else remaining same including focus (white balance switched to daylight).
1/500, f/2.0, ISO 400
So, 14 stop difference between with and without the Hoya R72 filter on front for this indoor scenario with daylight balanced CFLs. (so a filter factor of... 16,384 in this case)
I'll have to wait til next week to test it on film because right now I got FP4+ loaded in the MX (which drops off on the spectral sensitivity just before 650nm), and because it's supposed to be thunderstorming all weekend.
But I'm thinking when I do get a roll in there such as the AEU200, I can cut a short roll since I'm bulk loading, and shoot in 2 stop increments, aiming at an EI of 6~12 under broad daylight. But I'll have to factor in reciprocity failure, and lengthen development times if the exposure times meter a second or longer (AEU/Foma 200 's schwarzschild adjustments are 1s = 3x exposure, or -1.5 stops in aperture, 10s = 9x/-3, 100s = 18x/-4)