I think this is nice to start new year with some positive projects. What about helping Line6 in correcting User Manual and making Spec Sheet? All this to adress FAQ in future releases and better communication with users. I will use 2.10 OWNER’S MANUAL 90-20-0451 - B (For use with Helix LT Firmware 2.10) but i guess it refers to all Helix hardware family.
Page 7 "18. SENDS/RETURNS 1-2 These 1/4” ins and outs can be used as FX loops for inserting external stompboxes into your tone or as addit