The cab, to me, is a the tonal fingerprint. The amp portion is more about the gain level and some eq balance levels, but the cab plays a large part in the overall tone. I like to save a few of my favorite rigs' cabs as presets and then use those if I encounter a rig that I don't particularly care for and swap them out. I try my handful of saved cabs and if I still don't like it, I usually take that rig out of my Kemper. I kinda like that the cab separation algorithm isn't "perfect" because even though I use a few of the same actual speaker cabs for most everything, I get very different CAB results because of the different amps being profiled. Even profiles using the same exact cab/speaker can yield varying Cab results which just gives me more options when looking for tones later.
I have to ask, I think your switchback 212 is wonderfully balanced, but having bought the pack, I liked the cab on the OD100 a ton, ¿what are the specs? is it a 2x12? It sounds wonderful with the 69 Marshall (wonderful cleans, never expected that, then I saw it was from Eric Johnson, and it clicked, love it clean, love it overdrived, stock cab and with others), cab mix and matching gives another dimension to this.
My other question regarding this, I am hesitant to buy your IR packs exactly for those reasons, I do not know how much will be lost from the amp taking out the cab and putting one from an IR conversion. Maybe some magic is lost there. Is it better with the kemper cab pack? I wonder how much do you consider it would be lost, I am in the search for some immaculate 4x12 greenback cab sound with fatthead and a royer mic (gives a very realistic full expectrum of what you may hear in the room in my experience).