Is it possible to set the Guitar Thru Out in the back of the Helix Rack to send the tone from the Variax? I've got an external tuner that I like and can't figure out how send the Variax tone to it when I use the digital cable. It works like normal when I use a ¼ inch cable but then I don't get the automatic variax switching. How can I send the tone? Also, all of my effects loops are full...