Perfect lens for a project I am trying to get together for 6x9 format on my Speed.
In general, 65mm is the widest lens that will fit a Speed, due to the rear curtain. It will show the bed, however (with 4x5 film), so you have to drop the bed to use it.
If you want to use it hand held, you can dedicate it to your camera by calibrating the rangefinder with the bed dropped, or at least rigging a makeshift focusing scale.
They are VERY wide. I might consider using a roll film back, as well as trying some 4x5.
For a framing device, I used a coathanger to make an attachment for my sportsfinder so I can frame hand held with a 90mm (at least on the sides and top). It looks idiotic, and you have to take it off to pack up the camera, but it does work. I set it up by looking at the ground glass with the camera on a tripod. If you use roll film backs, you can try to find the proper Graflex insert for the top viewfinder, or barring that, have a machine shop make you one.