The original file I used has something like a 142mm opening for the parallax wheel. A bit large for anything I'm familiar with and still too big for tightening. I wonder why the original designer did it that big!?!?. I reduced it to something like 76% X and Y dimension, leaving Z (height) at 100%. Thingiverse is pretty stupid and searching is a pain, but if you look under "Scope Parallax Wheels", you can find the one I used.
Another file, Sidewhel Scope Mount Parallax, (yes, the spelling error is intentional) has three screws that tighten into the parallax knob. Says it's good for 31mm to 46mm knobs. That should take care of most if not all makes of scope. Might try that one in a couple days. My wife has my printer tied up for a few more days (honey do projects!)
Nautilus wheels are also available. Seem to be quite a few designs, if you want to spend the time looking.
I like the first one as it's wide enough to put a nice tape on.
Still pretty new at the 3D printing thing, learning as I go. Been fun, but I've had more than my share of fails along the way!