+1 erik_squires
Thats what I was thinking also, the 30A breaker won't kick off and that could possibly damage something and/or be a fire hazard.
I honestly do not see any meaningful advantage with utilizing a 30 amp breaker. I can understand that psychologically (More is always better mindset) it being seen as beneficial. In terms of actual sound quality performance I can see no superiority over a 20 amp alternative.
Charles