If you use the 80 lens for 35mm negs, you won't be able to print as large. With filters #4-5, exposure time will be doubled.

John Blakemore's Black and White Workshop is a brilliant book. Unlike the Adams books, you'll be creatively inspired after reading it. It makes the zone system very accessible without dumbing it down. He's also a truly gifted fine art photographer, and unlike many other darkroom manuals, the example images are stunning.