The versa tops are more functional and probably more pleasing of a match to the tank. Plexiglass maybe you can cut it to cover only three quarters of the top of the tank. Either the plexiglass or the versa top will be sitting on the inner lids of the top of the tank and you will still be able to put the screen top back in place on the top. The screen top is going to fit the outer borders of the tank.
The top of my tank is a little odd, in order to put the screen in I have to slide it into place, do you think a versa top would work with this kind of opening?