Hi Sapper,
All the numbers mean zip to me, all I can tell you is the Tornado boss is 20mm longer than the standard boss, this is because the shaft is 20mm longer. The are several designs of blade carriers but they all fit on these bosses. To get the wider cuts they just fitted longer blades. Even the 22 inch machines used the same diameter blade carrier as the 18 inch machines they just used the big blades that are used on the 24 inch machines
