Buhl Optical 9" (229mm) f/3.6 Odd Lens Hood Size

Hi all,

I just got this lens yesterday for making wet plate portraits in the shade. The lens flares incredibly easily (which may not be an issue in the shade) but I'd like to find a lens hood for it. The unfortunate thing is it's a weird size. It has threads in front that measure approx. 70mm which is a shame because that means I can't use a standard 67 or 72mm screw in hood. The outside of the barrel measures approx. 75mm, also a weird size.

I can't seem to find any odd size step up rings to convert it to a more normal size. I also can't seem to find a reasonably priced 75mm clamp on filter for the outside of the lens. The only one I see is an Alpa and because of the name and/or rarity people want $$$ for it. Anyone have any ideas? Sure I can use the darkslide to shade the lens during the shot but composing is even difficult with all the flaring. Thanks.

Rube Goldberg strike again:
Inexpensive 72mm filter, remove the male threads will it slip into the 70mm threads? If it does slip it in place and tape around the OD
and use 72mm hood; really don't know if there's enough meat to reduce the ring enough though.
If there's not enough material on the filter ring, is there enough on a 72-77mm adapter ring then use a 77mm.