My comment re Lyman having more info than you'd care to read was moreso regarding metalurgy, etc. ... that type info.
No doubt about it - you'll spend a bunch of time playing with cast bullet loads - part o' the fun. & I wholeheartedly agree - the manuals give you a starting point for what works in what they used. As in all else YMMV.
For casts, I really don't care how fast they go. I look for an accurate load. Especially for plinking/small game, doesn't really matter how fast they go anyway.
& me? Zip experience loading any belted anything.