The Stevens 350 is good to go as is. Put a single point sling on it and go(doesn't have to be fancy). The Tacstar Ithaca M37 sidesaddle does line up, but the Stevens 350 is all metric. If anyone can tell me the thread of the machine screws, please do. Savage doesn't know, at least those I have talked to. I don't have access to a metric die set.
Maybe replacing the recoil pad with a Limbsaver grind to fit may come to mind, but really it is heavy enough to absorb the recoil.
Also you should try a TNW Browning 1919A4 if you want to know horrid trigger pull. Yes horrid. The reset isn't bad tho.