After several years and MANY iterations of my rack (the perpetual hazard that comes with a lifetime of engineering), I couldn't be more happy with what I've created.
I had spent a ton of time experimenting with amplifiers over the years, and the recent introductions of fantastic-sounding amps at lower power and much smaller size is a big boost to the capabilities of a small studio. This one rack (pictured) has everything required for sound source except the desktop items (computer, monitor, desktop interface).
The flurry of reactive load box releases, combined with an absolute renaissance of speaker cabinet IRs has made it possible for me to sell ALL of my speaker cabs and retire my microphone. With a little time I can audition MANY IRs and choose a tone/response that suits my whims. I record a variety of styles, so I need to get a variety of tones. I had started with a Two Notes Captor Live, and have now moved to the much smaller Captor. I am using IRs by OwnHammer, York Audio, and Celestion. In my experience, the load IR is 60% of the guitar tone, so this makes a home studio very flexible.
Switching between amps had been the most annoying and difficult part of the system. I had been using a manual switch that worked, but the extra step interrupted flow. The MIDI-controlled KHE switch is exactly what I needed. It switches quickly on command, sounds fantastic, and has built-in protection and fail-safes to protect the amplifiers from running unloaded or driving each other. In my case, I use an Axe FX to control signal flow, act as a USB interface, and send MIDI signals to an Amp Gizmo (for amp channel control) and the KHE. This could be done without an AXE with a simple MIDI controller and effects plug-ins. I use the AXE because I can set up presets that are then easily used live as well, and I can use all of the internal amp models and effects. So it's an all-in-one system. For straight-up amp recording/reamping, the AXE is not required, and can be replaced with a MIDI controller (or PC) and an interface. So all control could happen in the DAW instead of the floor.
I can now control amplifiers and effects on a preset or scene basis, and spend my time playing instead of routing. Flow is ideal.
Moving forward, I am likely to move to amp plug-ins. I am dabbling with Amplitube and NeuralDSP, which are brilliant! But so far, I am happier with my amps than the plug-ins. The SV20H is a particularly wonderful beast. I'm also partial to the Mini Rectifier. I've done some A/B comparisons where I've tweaked the models to match the real amps. They get close, but don't quite reproduce some of the layering that I can get from the amps. Is that strictly necessary, since I'm going to double-track everything anyway? TBD...