The simplest way to connect two sets of speaker wires per channel to an AVA amplifier is to use Pomona stacking double banana plugs. One set (and pair of speaker wires) plugs directly into the speaker terminals on the amplifier, the second set plugs into the first set. Easy.
I do not recommend spade lug connections, especially trying to connect two spade lugs per terminal. They turn, they twist, they short together, they come loose and fall off, and when you take a pipe wrench to the connection to "really" tighten them, you break the speaker terminals clean off. That will really make a change in your sound you can hear.
Regards,
Frank Van Alstine