I could not have said it better myself, except for the last part.
When a blade has a thickness difference of .02" if you make the sheath fit both the smaller knife will rattle around in the sheath.
Also a convex grind as apposed to a flat grind makes a large difference
My old say 4 or 5 years ago sheaths may be a bit snugger than my newer ones, if anyone ever had a problem I would make it right. My sheaths are molded differently now & all knives are taped to were the tension is on the handle more than the blade.
Sheath making for me has been a growing/learning proscess for me over the 10 years I have been doing it. Listening to customer suggestions & experimenting with ideas I have.
Again no offense meant just clarifying.