In my way of thinking, the RCA manual is more of a "reference" as to what the various tubes will do. There are no real "cut-n-paste" circuits there, and only vague similarity to anything that Leo implemented. Leo leaned on the AT&T and Western Electric circuits a great deal at first, then modified those to suit his marketing needs. You can sometimes find the old Western Electric book, I've got an old GE book someplace, but really, all those pages as pertain to guitar amps are already online as examples when you look up ... 5U4GB for instance.
Now that you know the basics... study the old schematics, first Fender, then how Marshall copied a lot of it, and then Vox, and HiWatt, and Gibson. Study those schematics until you can draw them out in your sleep. Then start building some amps, and modifying them. Once you get to amp six or eight, you'll say... oh crap... why didn't they do... (whatever). And your idea will most likely work, as much of what controlled design was how an amp would fit into the marketplace.
And, keep in mind you're gonna get exposed to a lot of hyperbole. Gerald Weber's idea of forward and backward amps, or his idea of "co-planar" wiring.... are just baloney (thin sliced), but folks will take it as Gospel, until they learn the technical behind the rhetoric. You have to be your own BS filter, in other words. And that is part of the fun of it all... when you can truthfully call BS on one of those "experts", you know you've learned lots.