I would recommend going with roll film, especially if you are new to the IR film. Reason is that you will want to bracket.. a lot. At least until you get to know how each film behaves and what sort of filtering is optimal for the look you want. In my own work with various IR films, I've found it prudent to shoot at least two of everything. For subjects I really like, I typically do multiples of each exposure and bracket +2 on top of that.... which gets to be costly.
With sheet film, instead of bracketing the exposure, what I do is bracket development. Meaning that I develop one, check it out, and adjust the dev of the next one accordingly. But that leaves no spare negs, so I am usually tempted to shoot at least 3 LF frames of the same subject.
You have to do your own math, of course.
If you have any doubts about whether a back is good for IR, just surround it with foil or a metallic dark-cloth (normal cotton won't work). My own experience is that the problems are usually with the bellows, not the backs. Just keep the back out of direct light and load/unload in subdued light and you should be okay. Most of the concerns date back to HIE, which was far more problematic than our current crop of IR films.
P.S. I did run some Rollei IR through a horseman 612 back some years ago and don't remember any problems.