I' m not a pro, but I' ll add my 2 cents anyway.

If you shorten the cable, you will add to the pre-stress of the limb, which will increase draw weight. Shortening the cable will also increase draw length.

I wouldn' t pay too much attention to brace height or draw length. Take the string off, put tension on it, and measure it. It is more important that the string and cables are the right length, than things like draw length. Most manufacturers give you draw lengths that are longer than specs anyway. If the cable is the right length and you still can' t reach draw weight, I' d call the manufacturer and double check the correct string and cable lengths. I' ve seen them written incorrectly on the bows, before.