Good stuff—I’ve used both of these solutions live and I love them both. I am curious why you are just using the Marshall as a power amp? The beauty of the AX8 (and the Helix) is that you can bring it and your guitar to a gig, plug in power and FOH and you are good. The beauty of the SC20 is that you can bring an much smaller and lighter amp to a (normal club type) gig and be able to get some power tube drive and sound like the big amps cranked. Seems like your plan will work but seems to me won’t take advantage of either of the innate advantages of your gear?