Omega c-700 Enlarger to copy stand

If you use Prof Hank's suggestion of a block of wood,  you could take a cheap tripod and cut off the post, and insert it into a hole you drill into that block.  You would need to fasten it with at least one screw.  Then you would have the tripod head movements to adjust  your camera the way you want it.  The handle would need to be on the top so it won't interfere with pictures.  The length of post left on the head would depend on the thickness of the block.  It ought to be at least a couple inches, I think.  It could be more.

One more idea:  You might make that post a few inches long, and adjustable, so you could extend the camera from the enlarger frame out more, to accommodate a larger object to be photographed.

On the other hand, you might look for, and buy if available, an old Spiratone tripod that can be set like this:

Spiratone tripod--old

There are probably other brands that will do this.  I used this setup to copy slides and B&W negatives, and small objects, coins in particular.  The camera is a Konica-Minolta A2.  I used it with the lens extended, and the "macro" setting.  This works, but it is awkward with the tripod legs sticking out like that.  I had to be careful in my movements not to bump a tripod leg and knock it all out of alignment, which happened.  Using the enlarger frame you have would be a good way to go; more compact and out of the way.  It could stay put.  A tripod is only a temporary setup, unless a person has a lot of extra space where it could remain in place.

Many thanks to everyone with your suggestions. I'm not very handy, but I found a small cheese plate that may work thanks to a youtube video. The only handy work I will have to do is drill two larger holes.