That being said...with figures this small, I don't find that it matters to use an actual "priming" paint. I "prime" my ships usually with one of GW's gray colors (Codex Gray for my RoF) out of a standard GW paint bottle, thinned with a little water so it doesn't obscure the detail. I pick the priming color based on the overall scheme I have in mind; darker primer colors work better with darker paints, for example. So if I wanted to paint my Blazing Suns in yellow, I'd probably prime them with a very light gray.
But that's just me. The farther I get into this hobby, the more I realize there are many ways to do things, and usually none of them are wrong. Some techniques may just take longer than others to get your paint scheme to where you want it.