The Tiffin will work, but is known to introduce a slight (correctable in post) green cast in blacks at all levels of ND. The tests done by Ryan Walters
http://www.ryanewalters.com/Blog/blog.php?categories=IR with the Schneider Tru Cut filter shows that the 680 (like the Tiffen above) is best for the BMCC and has no green cast. But conversely, the Schneider 680 allows more IR through than the Tiffen at higher NDs, but this contamination basically only starts to show slightly with a .9 ND and even a 1.2 is somewhat passable without additional correction in post. So based on these tests, I would say that the Schneider True Cut 680 is more neutral than the Tiffen up to 1.2 ND. Above 1.2 ND, both the Tiffen and the Schneider will need post correction, one to neutralize the green and the other for red. I opted for the Schneider because it needs no correction up to 1.2 (depending on how critical one needs to be), where the Tiffen requires correction for the green cast at all levels of ND. Pick your poison.