Ah, good to hear - the JPG community seems to be growing! :-) Probably that’s more and more possible because the in-camera processing gets better and better.
I heard that a simple 80% gray color check is much quicker bit sufficient for most cases. But the processing time would still be similar. And there are still changes in the light over the course of the day. But I gather that’S the only good way to handle differences between cameras? They can be quite obvious, even with the same white balance setting or even RAW developement. What app are you using for those calibration profiles? It cannot be done within Rawtherapee?