An adapter that uses the camera lens to shoot through the eyepiece of a spotting scope or telescope should mount to the lens threads, so there may be no significant difference between an adapter for a 35mm and a medium format camera for this, except for the thread size, which could be resolved with a step up ring. You might also be wary of whether the eyepiece mount can support the weight of your medium format camera.
Most important, I think, would be the question of coverage. If the image doesn't project to larger than the area of a 35mm image on MF film, then there isn't any advantage to using a MF camera for this. You can test this without adapters, just by positioning the camera to look through the scope and seeing what kind of image you get, and considering whether it's worth the trouble of acquiring the adapters to do it all with good alignment.