100% spinebreaker with backbreaker edge gives a horrible success rate, from my perspective nothing significantly different from 50%. Anything less than that and trying spinebreaker is asking for a beating - 3 rounds lag on failure. Just be glad you've gotten round my other primary lagging method on shamans. You didn't look like you were ever in much danger of actually dying to spinebreak/trample, or anything else I can do while you maintain your buffs.