I tried ot make these at 41, and got owned hardcore, lost 5 helms and 8 sheets ; ;. Only made 4 helms successfully, and got either a .3 or a .2 each successful synth.
I have 44 skill and just got a skillup off of this. It would make more sense if the cap was 45 for this and other recipes, considering other goldsmithing CP item upgrades have caps of 25 and 65.
personally I think there would be less confusion if they simply put a ? instead of 0. albeit, you wouldn't be able to craft the item unless you were the proper rank within the guild... but it's still quite confusing.