I only have the RY of those PUs and that as 6 string, but from what I all around know the BD is the loosest of the three, lots of (center)mids, therefore great for baritone instruments.
The Emerald bridge is very bright and therefore capable of handling extented range guitars and modern metal more than one would think right away. IŽd say this is an option for you.
The RY is a bright PU too, though I believe not as bright as the Emerald. The high mid spike in the RY definetly gives it a lot of cut, it generally is a very agressive and lively PU, breathing rock like nothing I have heard so far (the Crawler comes close, but in another way). Lots of overtones in there, generally a very organic sound. The general character is modern with a vintage throwback in there. The bottom end is very defined and tight, giving you not so much boom as punch. Also it is very suseptible to height changes so expecially the bottom end response can be fine tuned a great deal.
IŽd say you would fare best with the RY. I can imagine it to work very well in 8 strings and I know it can go from classic rock to absolutly modern metal (Red Seas Fire for example). Enough chug in there too imho.