I'm new to the Kemper but I have a Stage as of last month and have played out 2 times using this for power...
https://www.musiciansfriend.co…ture-250w-guitar-amp-head
its 150wt @ 8ohms (I just plug into the effects return) into my 2x12 and it also is a 2 channel head as a backup. It fits in a large backpack along with my Kemper and all the cables and power I need for my gigs so it might be a plausible option as it is small and light weight.