Krockmitaine, I used the 72 filter with 4x5 because my lens wasn't fast enough for the 87. With a #87, I would need to go ~10-11 stops over normal exposure, and then with an f/8 lens... that might push the exposure into reciprocity issues. With the 72 one need only go about 7 stops over normal exposure, under sunny 16 conditions. I also sometimes prefer the slightly subdued effect of the 72. With so much foliage here and the deep shadowing, I think the 87 would have been too contrasty.
Ryan, 11x14 IR film? What are you going to do, aerial recon?! Well I am sure the results will be amazing.