Furutech Outlets and Wire Gauge

Have you used the Furutech GTX-D outlets?  What is the largest gauge wire that you can use with these outlets?  The website says, 12 AWG.  I'm guessing you can go a bit larger.
I just installed this outlet with 10 AWG. 
So, think 8 AWG would fit?
Yes, but you will have to use spade connectors on the wire ends in order to connect to the receptacle. Bare wire that large will not fit around the screws.
Think I will just run 6 AWG from main panel, then drop to 10 AWG in a junction box to outlet.

Have you tried the Furutect Outlet covers; very pricey!  Wonderng if they are worth the money.

I have not but a friend of mine did purchase one. We all listened to it and all agreed that it didn't do a damn thing to enhance the sound. Looks sharp but that's about it. Save your money !