I upgrade fabic coats for priest to +7, so this is what item works for me for this....
Whenever you upgrade them, when there is noone else, or maybe one person at the anvil (So it doesn't mess up your pattern), do not upgrade one at a time or all at a time... What I do is I upgrade 2 at a time, and when one fails, go all the way to +7 on the next.
So far I have not gone through this with losing more than one... If one breaks the other one doesn't. Im not sure what will happen if there are multiple people at the anvil, but I do it by myself usually..
Tell me if this works for you too
