I LIKE THE SPEER #8, BUT WHAT DO I KNOW!
The Lee's are the most comprehensive, but they are also an advertisement for their product. If you can wade through that, get it.
Actually, when I START on a load, I ALWAYS start with the powder manufacturer's data and all of it can be had online. Now, I may, no, I do, venture way away from that BUT that is where I START.
(I hope I made that clear about where I START, not where I end up!)