I wouldnt be surprised to throw a breaker just due to turning everything on at once. Turning things on one at a time gives them time to reach stady state current draw. I don't think you'd hurt the machines tho in any case.

I wouldn't do it but its more because I like the feeling of using the power switch like an operator

They don't run at a constant 6-8 amps. Most are rated that high but they don't draw that peak amount frequently. You wouldn't be able to have more than 1 or maybe 2 turned on in a standard house circuit if that were the case. I believe here in Canada our usual circuits are still fused 15A @ 110V, and in older homes the circuits are often only 12A if I recall.

I've seen 8 machines in attract mode on one circuit and it required at least 2-3 to actually be in full use before a breaker went. The Iron Man magnet helps increase the current draw btw