I'm holding a Superclamp in front of me so that the big handle that tightens the jaw and the t-handle that tightens down on the 5/8" stud are closest to me, and the chrome spring-loaded button is to the right. So basically, if you inserted a 5/8" stud it would point vertically/upward.
Take a look at the 6 holes on the surface. The one closest to you is obviously for the 5/8" stud. Think of the other 5 as all four plates on a baseball diamond. The center one being the pitcher mound, of course.
The t-handle that tightens down on the 5/8" stud is 1/4"-20 thread. The pitcher mound is also 1/4"-20 thread. Home plate and 2nd base- I'm unsure of thread count. Could be metric.
Regarding your question about mounting the 1/4"-20 male of your monopod- it will work, yes. But I sure as hell wouldn't do it. Taking leverage/mechanical advantage in to account, I'd be scared to death some spunion would grab/bump the pole and either bend or shear off that tiny 1/4" connector.