What grit to sand base coat before clear coat

[Cleve]

Painted our cobra with Diamont base coat. Maroon. Turned out great. I am getting old so did not paint on the clear coat. Planning on doing a light sanding tomorrow. Then a fourth light base coat. Then clear coat. I have been told to not sand it at all. I have also been told to sand it and use 600 then 800 grit, (tech support from paint company said 600-800. He said 1000 grit wasn't rough enough for the 4th base coat to adhere to), Just wondering what is the best solution for painting the 4th basecoat after waiting 24 hours? We plan to paint the clear coat right after the base coat flashes.
Thanks
Cleve

[Jeff Kleiner]

If it has any metallic or pearl do not sand it. If it’s a solid you can doo 600.

Jeff