You've got it. I measured the width of the narrow portion and depth of the dove tail on a factory holder and machined a slot to match. Then I measured the width of the wide portion of the dove tail on a factory holder to use as a first approximation for how deep I would have to cut each side of the slot. 3/4 of the way thorough to the approximation target I switched to comparing the width measured between 1/4" drill shanks to that of a factory holder. Worked like a charm.
If that doesn't make sense PM me.
Makes perfect sense Craig.
Nice job!
Thank you!