Michael Richards , Dec 01, 2007; 12:52 p.m.
A lot depends on your setup, but I'll pass on my experience with B+W 092 (89B equivalent) versus 093 (87C equivalent). The latter is opaque and needs about 2-3 more stops than the former with HIE. If you deal in filter factors, that's about a 4-8 multiple. I'm not sure how it would work out with the Rollei film, but it's probably a good starting point for bracketing. Good luck, and please let us know how it works, if you try it.