Sorry for triple posting, but I got a reply from Bryan Pope.
There is nothing in the rules that says bonuses from sources of the same name do not stack.
The rules say that you cannot have 2 spells of the same name attached to the same object. Therefore you cannot have 2 Lightning Rings or 2 Bear Strengths attached to yourself. However, if they could be attached, the bonuses would absolutely stack!
So, you absolutely could put out 2 or more Tooth & Nail conjurations, and have the effects stack. In fact, we intended and were hoping to see some of that!
If you don't mind, please post that back to the BGG thread for us and thanks or the help!
The rules say that you cannot have 2 spells of the same name attached to the same object. Therefore you cannot have 2 Lightning Rings or 2 Bear Strengths attached to yourself. However, if they could be attached, the bonuses would absolutely stack!
So, you absolutely could put out 2 or more Tooth & Nail conjurations, and have the effects stack. In fact, we intended and were hoping to see some of that!
If you don't mind, please post that back to the BGG thread for us and thanks or the help!