I own a 393PCX in The Moorings fleet on Tortola which has twin 150 Volvo's. Your cruising speed will be about 11-12 knots. If you have the 393PC with the twin 110 Yanmars your cruising speed will be about 8-9 knots as previously stated.
We usually put the young kids in the forward port side cabin because of the forepeak.
The starboard side is the owner's cabin with a very large head compartment with a large shower. The port side has a wet head.
You will have plenty of room on the vessel with 6 people on board....the fly bridge is great.

Enjoy your cruise.
Billy