Chris
You ask for examples of set ups, the following may be of help
The first one is largely self explanatory
**LINK**
In the next one, the square piece of steel with four corner projections, photo 25, is being used to hold the collet whilst being slit. It could have been a larger square with a round hole but I was using a smaller size scrap that was available.
Being square it enabled the collet to be easily turned though 90 degrees for each slit. The pieces of steel on the cross slide set the height and the top one is a side fence to ensure the collet is slit central for each slit without the need for further measurement.
**LINK**
Photo 27 shows that I also used the simple fixture when milling the anti turn notch
Click on the pictures for a larger view
Harold