Par4QC I'd start by tipping progressively, as with a "regular" set. I guess you could play around with trying to guess/calculate the impact of a slower than "normal" swing speed in the longer irons and a bit faster in the short-irons (i.e., the resulting loss/gain of SS that would come from having a slightly shorter or longer shaft than "normal"), but I think you're splitting hairs pretty fine when it comes to average players. Tipping is a long way down on the list of specs that are going to have a major affect on most peoples' games.