With regards different lengths, you have always had that in the same tin. A dies a die and should come out exactly the same many thousands down the line.
One thing JSB have never answered is how many dies go in to one tin!
Express with flat in shirt dont group as well but are more stable above 3mph winds, still got 13 tins left, i quickly sold the conventional last year as they were unpredictable above a breeze.
Also have early Mozzies when they were proper Webley with flat in the skirt, plus Rob had some a few years ago a lot newer.