Hi Tad -
I am thinking about doing the same thing in the future (already have a 1 oz slug mould). The Lyman shotshell book has several recipes using various components and hulls, but I don't have it in front of me right now. As you know, you definitely need a good safe recipe to load from. As for a cross-reference chart for hull interchageability, I've never seen one. It would be useful however if the ammo or component manufacturers would make a list of interchangeable hulls (like the Remington Premier, RTS, Nitro, etc...)
You have to be careful with some of the older hulls though. Remington made several other case types over the years. I've been trying to find recipes for some Remington 20 guage hulls recently and dug through a box of pick-ups. There were 3 different remington hulls, RTS (or premier), SP, unibody as well as Peters hulls (similar to unibody). If I'm not mistaken, Remington also made a plastic hull with paper basewad.
You really need to find a load recipe for the exact type of hull you are using. Depending on the compents, you can get to an overpressure situation very easily. Lyman shotshell manual has a hull identification section that is pretty good. One other option is to use the Hodgedon powder data. it uses a 'range' of powder charges for each hull and components where you stay within safe pressure limits. Most other data gives you 1 powder charge with a given set of components. One potential source for data is used bookstores and Flea markets where you can sometimes find older hull recipes. Unfortunately sometimes the components for the given recipe are no longer available (Rem 97* primers for example).
I keep a large variety of hulls, wads, powders and primers (accumulated over MANY years) because I (like you) pick up hulls almost everywhere I go. I can't stand to see a good hull thrown away!! Load safe and shoot safer!!
Regards,
Hazmt