Read the comments here and attempted this with master guild support, off-hand, at lvl 10 armorer. Was able to make using fulfillment and master touch support from other crafts I have leveled without too much difficulty. Received 233 armorer points for this, so my estimate would be that it is a lvl 14-16 synth. If rumor is correct, each craft has an elemental affinity, such that if you are strong in the aligned element for that particular craft, you have an easier time of it. Not sure if I buy that, but I do know that I didn't have as much of a problem as others seem to have had in making these (for the record, my character's elemental affinities were between 41-47 at the time of the crafting). Was able to go on and make the bronze rings to repair my gear with no problem at all, so my guess is that the bronze rings are probably around a lvl 13 synth or so. Hope this info helps!