Thanks for all the good suggestions and advice.
I forgot to mention that I am mainly using my Toyota 45CF for field work and lanscapes. I agree that keeping the camera as high as possible is a plus. The main reason for seeking a focusing hood is because I just can't get used to the idea of dark cloth.
Well... There's really no substitute for getting your head in a dark place together with your ground glass, especially if you use and movements whatsoever. Viewing hoods are an alternative, but not optimal by any means. They are fiddly, tend to take time to mount/dismount are easy to drop, take up room, are fragile, etc.
So, I'll recommend two things. First, get a good Fresnel screen for your camera if it doesn't already have one. With a good Fresnel and adequate light you can often get by without using a dark cloth at all in the field. My Wista DXs have no hoods, etc. and I often focus and shoot without the dark cloth.
That said, when you need to, a dark cloth is one of the more comfortable ways to work. You can move your head around easily, check corners, tip your focusing loupe to match the angle of the light hitting the ground glass for better viewing, etc., none of which you can do with a viewing hood. I'd at least try to get used to using a dark cloth before shelling out for an expensive hood. I'll bet that with a little familiarity you will learn to like it. If you find you can't stand it, then you can always get the hood later.
FWIW, I use reading glasses at a strength to get me 8 inches or so from the ground glass for viewing and rough focusing and then a loupe for fine focusing.
Best,
Doremus