We've whipped up a profile-matching normally-closed-switch 2button SideAux for the Boss 200 Series pedals!
This pedal also works for the GT1000-Core, as it shares the same profile as the 200series pedals.
*TRS Cable required, https://pedalnetics.com/product/switch-trs-cable/
Does exactly what I need it to do. Built to last, and looks great next to my GT-1k Core.