I talked to Ian about the power brackets when I visited last year. I have QS4s and on-wall M3s, not sure if QS8s are different. I found that i was trying to tighten the clamp on a very short (1/4 inch or less) section of multistrand wire (14 gauge, I think) and the wire slipped out as I tightened - several times and yes, expletives followed. I ended up drilling a deeper recess in the bracket to allow a good 1/2 inch of stripped wire under the clamp. Much easier!
I have no concerns about the quality of the connection.
