here's the excel file i made. the top part is if you have round ports, the bottom part is for one slot port on the side of the box (like moe lester designs). you should be able to figure all of this out by hand pretty easily though. once you get the final box volume, enter that and the port dimensions into winisd (you can make a project with any driver), and it will tell you the tuning.
hope that helps,
Ben