Make sure that you call him or email him because he'll obviously give you the answers to your specific questions.
When I spoke to him he said that you'd have to move the index pin on the bow form closer to the limb tip. If you want a 66" bow, move the index pin 1" closer to the tip (and so on).
He'd give you the best information on what stack you need for the weight that you are trying to achieve if you call him.
Good luck and have fun!