Thanks a lot Rob. I didn't have a chance to take a look at these yet, I had to machine about 60 parts today on this fixture so I simply manually edited the gcode file and added 2 stops to put the hold downs on. I've attached a photo of it in operation.

With this production I've completely converted to BobCAD in my workflow. There's still lots to learn and understand. I see many places where I can make some optimizations to decrease some more time.

One thing I'm trying to understand is the Rapid Plane. I understand the clearance plane - Z is moved to this height to rapid. But the Rapid Plane seems to be used within an operation. The default is .2. If I have my hold downs installed, Z needs to be at .6" or the tool will crash into them. Unfortunately, this means that each time the tool is retracted and reinserted - to do 2 depth passes for instance - the tool lifts to .6" even though in this case, a really small lift like .1 would have been fine. It seems that there should be independent control for the Z lift when the tool is simply withdrawn and reinserted at the same coordinates from when the tool is withdrawn and then moved to a new coordinate. Am I missing something or is this the way it works?