Well, on a Paladin, you can open the book at level 1, but have no spells in it (just tried that on my own char to make sure).
kamal_ said in an older thread that spellcasting classes can be problematic because of the amount of hardcoding. And I'm guessing that's exactly what is happening when I use the default Paladin settings for the class. There is probably some hard-coded script somewhere that filters the spells for a Paladin. Since my class isn't a Paladin exactly, that filtering is gone.
For instance, I just now when into some of the scripts in the data director, and there's a lot of checks against the standard class constants, for things like Dispel magic, etc.
I'm guessing my custom class would break all that stuff.
So, I think the clear winner here is to keep him a Paladin, and then use some scripting to manually give him some feats (like the deity weapon feats), and possibly revert back to your scripts.XML if I feel bonus feats are necessary.
He needs to be a true Paladin to keep from borking the whole thing up apparently.