Tips for painting glowing lines when using slapchop?

Hi all,

I have several armies done in slapchop and I'm pretty happy with it. But I'd like to paint some necron vehicles for a friend and I'm curious how to paint the classic glowing lines when using a slapchop procedure.

Does anyone have any advice? Was thinking of putting white acrylic into the lines and then a bright contrast over top - but wondering if the white acrylic should go before or after the surrounding areas have had a coat of their contrast colour.