Figured it out. User error brought on by never having to do this on T3 and having the answer buried in the docs and not obvious (to me). I think the real key for me was that switching chords was not blindingly obvious. I spent an hour looking for the answer and it was in special chords, but even then I glossed over it.
Switch between configs using T0F4M. Below, for more verbose:
-Convert your config to v7
-Open cfg in tuner and save. (For it told me my converted cfg didn't have system chords, which it then inserted)
-Copy to Twiddler.
-Unplug
-Replug
-Press T0F4M. Left LED is 1.cfg, Middle is 2.cfg, 3.cfg is right LED
For Tony and Eric I would suggest two things. If it turns out these are already present and I simply blanked on them then apologies:
1) make this key chord extremely obvious on any page that mentions uploading your cfg to your device. It's essential to getting the cfg to work.
2) Have T4 default to 1.cfg. It seems to default to 0.cfg, but it seems like that should be a read-only fall-back for if the other configs don't work.