Bausch & Lomb Planetograph F-8 and "Three Focus" lenses?

[HalideReducer]

I have two Pony Premo 6 cameras, one made by Rochester Optical and the other one after Kodak bought them out in 1903.



The older one, on the left, has a shutter labeled R. O. & C. Co on the top, and AUTO on the bottom. It has 1, 1/2, 1/5, 1/25, 1/100, B and T settings. It has f-stops marked for f8 through f128, although there's a tick to the left of the 8 so maybe it's an f6.3 lens. Amazingly the diaphragm seems to work and it fires on all settings. The lens is labeled Bausch & Lomb Opt. Co. Patent App'd. The front and rear elements both unscrew. The outside of the front brass barrel is labeled Three Focus.

The newer one, on the right, has a 3.5" square lens board. The shutter is labeled Eastman Kodak Co. Succ'rs to Rochester Optical Co. It has the same shutter speeds and aperture settings, and the diaphram and aperture blades work great. This one will fire on all settings but the shutter sticks open when set to 1s or 1/2s. Inside the front lens ring it's labeled Bausch & Lomb Optical Co 5x7 Planetograph F-8 E.F. 8 1/2 In.

Both have a 32mm outside diameter and look like a good fit for a Series 5 or 6 push-on filter adapter.

I think I need an air bulb remote shutter release but I can fire it with the lever on the side of the shutter.

1. Does anyone know anything about the "three focus" lens? Focal length? Is it meant to be convertible?
2. Any suggestions on unsticking the slower shutter speeds on the Planetograph?
3. Between the two lenses, any thoughts on the image characteristics between the two?