At the price point you mention, you won't have a lot of room for modifications, restocking, or upgrades, so I would suggest buying a gun you like in its present configuration, either out of the box or the way you find it. I would agree with the 30" BSS, the Model 23 Heavy Duck, an RBL 30" or 32", Beretta Silver Hawk 30", or a rusty Model 21 that hasn't been shot much. The Model 21 should be rusty only to keep the price within your limits. In your situation, I would order the RBL in the configuration of your choice.