VC17
I just (well last summer)did the bottom using VC-17 Extra, I believe but don't hold me to this that before the Teflon was added it was called VC-17 then Teflon was added and the VC-17m came on it, with the VC-17m Extra you get the addition of Biolux. I didn't use the VC Tar undercoat, but after talking to a Interlux tech I chose to use Interprotect 2000 in its place. I also rolled rather than spray. Mine was a rather long project as lightning had hit the boat. I added the link to the Interlux folks maybe you can find the answer your looking for there.