The Masters spellthread enchant, while obviously not the best thing in the world for a tank, is rated at 0.
It provides 80 stamina (in addition to the obviously useless 95 intellect)
However, the Heavy Savage Armor kit is rated at 14, where it provides only 44 stamina and no other bonuses.
Obviously, 80 > 44, and therefore teh Master's Spellthread should be rated at least 14 for tanks.
I would suggest even higher as the highest 15 enchant is only 55 stamina and 22 agil.
Something around 16 pts maybe? or make it ties at 14 or 15 because the int is a penalty.
The master's spellthread is an unconventional, but cheap and easy enchant to the legs of a tailoring tank/dps and a pretty good option until one wishes to dole out the cash for the new epic ones.