Mauser,
I am going through the same exact thing you are. Have you looked at the Nikon Monarch or the Nikon ProStaff low powered scopes? If you haven't...they are really sweet. I really like the Nikon scopes...they are the clearest scopes I have ever looked through. I have a Rem 870 SPS-T with thumbhole shotgun that isn't tapped or drilled either. I called the local gunsmith here in mytown and he highly suggested going with the drilled / tapped weaver rail instead of the saddle mount. He thought that it would hold up better to the recoil that a turkey load shell would produce. I don't think he was saying that the saddle mount is a bad way to go (don't mistake what I am trying to say), he just recommends the weaver rail instead. Take a look at the Nikon scopes though...I think you will be amazed. If I remember correctly, the Monarch line has a 95% light transmission while the ProStaff has 90% light transmission! The Monarch will run you around $250 and the Prostaff around $125...