Hi Gluebeam,
Have done this myself; a few tips for you:
1. Spend as much time as possible cleaning and preparing the stock before oiling it. You need to get a smooth, almost shiny finish before oiling.
2. Use boiled linseed oil and to start, mix with about half as much pure turpentine. The turpentine pulls the oil into the wood, but it must be the pure turps and not the cheap turps substitute you sometimes see in hardware stores.
3. On later coats you can reduce the turpentine, but I always add a little as it seems to help.
4. As to how often to apply, I stick to the old sa