How should I prime my minis?

Good morning all 🌞

Today is a rare dry winter day so I want to prime the Maggotkin models I've got so far (Harbinger, Rotmire and Nurglings) however I'd be extremely grateful for advice on what color to prime them.

I'm planning to heavily use contrast paints and metallics to do the bulk of the painting so I thought I might prime them black and then give a heavy dry brush of grey or white but my question is would this work or would I be better using Grey Seer or something lighter?

Many thanks in advance