Mark, great to hear you are building as you go. You have to do this. When you are designing and copying you have to make changes along the way. Having access to a water jet is awesome! I have to improvise.
My first bellows was from Western Bellows for the 8x20. The 11x14 I got lucky and scored a perfect bellows off of e-bay for 100.00! My 14x17 bellows I had done by Custom Bellows in England. Both of the bellows I had done are great and worth every penny. Getting the bellows done saves a lot of time but it adds to the cost. I just know that I'm not good at it. I just find cameras that I like and copy or use the design as a guide and add my own touches. Be prepared to make adjustments as you go. Makes you think.