Sounds like a reasonable plan to insure the profits on your remaining physical Silver holdings, especially if you are content to continue to hold a core position in Silver for an indefinite period of time no matter what the price does. As for strikes, you probably don't have to go too far out of the money to provide good protection at reasonable cost. And as the price of Silver rises (if it just keeps going) I assume you would raise the strike price of each subsequent put purchase.

As for Natgas, yup, the chart seems to be rounding into form nicely, and is ever so close to triggering a major upside move. I figure a weekly close above $4.50 should get the ball rolling on that one...