There are two schools of though on this:
1. 6 oz cloth over the 4 oz. on the deck. will make the board stronger than a 4 oz. lap to the bottom but use more resin in the hotcoat.
2. 4 oz over the 6 oz will be a bit easier to lap and use less resin on the hotcoat to fill the weave.
Either way is OK. It's up to you