I just painted my 68 medium gray metallic. I used a acrylic enamal single stage. This was my first paint job so i did'nt want to dump a lot of cash into my first job. How long should i wait before i wet sand? What grits should i be using? When i finish wet sanding do i need a buffer or a polisher? Thanks in advance.

Well, this is an easy one, NEVER. You can never sand a metallic single stage paint and buff. You will cut into the metallic's layers and make a total mess of the thing.

If you want to LIGHTLY polish it with a buffer, ok, but it has to be VERY, VERY light.