Bert, since you have a 121/8 SA, by all means use it even though 121 mm isn't very wide on 4x5. You really should come up with a way to measure its flange-to-film distance when it is focused at a distance that makes sense (hyperfocal distance @ f/22, perhaps?). This because the lens' actual focal length and flange focal distances are probably not exactly what the Schneider brochure says.
Originally Posted by TheToadMen
Yes, a single shutter speed can be limiting, especially if you don't know what it is. Buy your 210/4.5 Heliar's Compound a CLA.