I've seen those on eBay, they seem a little suspect as they indicate that the black interior coating may flake off if cleaned. How is the quality of them?
Above is a 35mm~65mm helical focus tube with a hasselblad interface and a 52mm thread on the other end. I used a 52~40.5mm reducer, which was hand filed out to 41.6mm. This allows a Copal #1 shutter to be mounted, which the Imagon optical block was designed to use. You can easily mount any LF lens that was designed for a Copal #1 shutter. The Hasselblad flange distance is 74.9mm, so that, along with the focus helicoid, adapter ring, and copal shutter spacing (20mm), and the offset for the Imagon achromat block was just short of 130mm, which allowed this Imagon to focus just pass infinity (~120mm to the Copal shutter).
The Helicoid (as they call it) is well made, anodizes with a flat black paint layer on the inside - which has not flaked off on mine. I'm sure if I rubbed the inside painted surface, the flat paint would come off. There is a tiny amount of play, but pretty good for the price.
It works best on a 200/2000 series Hasselblad using the focal plane shutter, but of a 500 series, you would focus, close the Copal shutter, open the barn doors, trip the Copal shutter, close the barn doors - a very similar work flow to any large format photography. Since the OP was looking at using Large Format lenses, this is a possible solution. The only thing I might do different is get the focus tube with the 65mm thread (instead of the 52mm) which allows the larger Copal #3 shutters, and use the dedicated 65mm-copal shutter reducer instead of modifying/building your own.