Nothing of "theory" about it. Basic idea, it's a Newt aimed at a Cass. You have to validate the quality of the Newt to a good high degree, and the F/D doesn't matter. Dave was correct. Carrying it a step deeper-
What -DOES- matter, is the quantification accuracy desired!!!!!!!! That requires iterations that ZEMAX can do easily. Along with our 2 'MAX designers.

(Did I get it right, Mike? If not just tell me to shut-up.)
Mark