Pat, that's a little different approach than what I've done.
Doing a flemish, I'll cut all the strands and stretch each individually.
After the string is on the bow, I'll twist it up a bit short (1/4" ish) then I'll burnish as you mentioned.
I think the string (for me) comes out rounder in the end.
Burnishing seems to make the string longer too on the bow. Probably from getting the strands tighter together and getting some of the wax out. I'll get very little stretch when it's ready for use.
Just another way to skin the same cat.