I've used a Bower IR72 off ePrey ($47 for a 77mm in 2010) with Rollei IR400 quite successfully. Take an ISO 400 reading, add 6 stops and bracket, bracket, bracket! I agree tests ahead of time are to be highly recommended. Since our eyes don't see IR, we are denied a chance to do a lot of intuitive adjustments.

Most recently I used a Wratten 89B (~695 nm) which was OK, but not quite as good as the 720 nm filter in the infrared effects, and I would expect a 25A to be even less good. I think the more ordinary red filters worked with the old Kodak stuff because it had a very wide sensitivity outside the visible spectrum, a sort of 'area under the curve' biased in that direction.