I don't think it's uncommon to have a manufacturer make the 58° and 60° four or five grams heavier than the 52° and/or 54° (with the 56° being different from both - since the SW is usually preferred to be heavier?). Or maybe I'm just used to it - as all of my recent Maltby sets have been that way/weigh (MMB, TE, TS1)? Anyway, accordingly, I've built my SW and LW wedges at .25" shorter length than my PW and GW. darpar is likely right though - I probably wouldn't notice much, if any, difference in a wedge, if I built them to all the same length.
