There is a lot of data out there but be careful to only get it from manufacturers of components, equipment, etc., or from places that have pressure testing ability. Uncle Fud's data that has blown up five guns or from some off-the-wall website, is NOT good data. I have my own loads but they are all developed from manufacturers' data and held within their minimums and below their maximums for my guns. Part of the fun is finding what shoots best in your gun! Just to get started I'd use the minimum load data from a manufacturer and go no higher than the middle if you're going for CAS shooting. If you're looking for a defense or hunting load then I try to stay below the listed maximum. Sometimes you will get to your gun's maximum long before the published maximum. Keep track of your loads in a diary or journal so you can repeat the goods ones and avoid repeating the not so good or bad ones.
Great bullets are available on line from: Home
You can also order from Graf & Sons. There are other cast bullet makers out there who are very good and you can find them in the Cowboy Chronicles, NRA publications and Reloading Magazine as well as other shooting publications. There are any number of regional casters, too, and I don't know all of them. The regional ones seem to be in business for a few months or years and then disappear just when I'm ready to reorder.
I have been casting most of my bullets for 40 years now. It is a fun hobby itself but takes another investment in good equipment. Lee has some good starter tools.