Dedicated 20 amp lines/should i use a sub panel

Happy New Year to all!!

I am about to install 3 - 20 amp dedicated lines for my stereo. I still have space in my 200 amp main panel but was wondering if their is any benefit to installing a 60 amp sub panel for the 3 audio circuits , also as i am using 10 gauge wire and its not the easiest to manipulate should i hook up the bare wire to the receptacles looped around the screws or inserted in the holes or should i use spade connection's. any advice would be appreciated.

Thanks in advance
Chris