Hi DW33,
To answer your question I used the Accushot High mount 1 piece scope mount for 1 inch scope tubes. They also sell 1 piece mounts that are made to fit the 30mm scope tubes so if you decide to purchase one make sure you get the correct one for your scope.
The othe thing to consider is the question of whether your barrel has any droop factor. RWS are noted for having barrel droop designed into the rifle. Some rifles are more pronounced than others. My 350 had droop and in my case I chose to shim the rear of the scope mount to correct the problem. I am not advising you to shim any scope you may have,,,,, that is a personal decision that one must make after doing all the research and deciding for ones self. Keep in mind it is possible to damage a scope during shimming if you're not careful. In my case I chose to take the chance.
If the scope mount you have on the gun now is working then why change it? If all you need is a good scope stop then check out Rich's website. I believe he sells a modified GAMO scope mount that he says hold well. Check out his website,,,, he really has a lot of good stuff and if you have any questions all you have to do is email him and I'm sure he'll steer you in the right direction.
Jeff