This is really just a quick note to say that after a total of about 4 hours playing round with the Helix through my Blackstar Artist 30, I'm getting some great results.
I really want Helix for live performance, and to be able to switch between a few different basic amp sounds. So I'm going 4CM through the Artist. The Artist is a great base amp for this type of thing - tons of clean headroom, and a nice neutral power amp section. I bought it to replace an Orange TH30, which was an amp I totally loved, but which really can only do one thing, and had notoriously little headroom.
I have to say that experience so far with the Helix and the Artist is really good. The Cali Rec Amp without any cab just sounds fantastic, and is going to be my go to solution for most classic rock numbers. It sounds much grittier and more authentic to my ears going through the Artist than it did going through a stagesource L3, but that's just my ears.
If anyone is wonder about a good solution for live performance using a real amp, this could be it.