Thanks, the issue was indeed n_out=classes. I was really just puzzled why this particular class of models has this parameter, but your response and another one that someone else just pointed out to me (Xresnet Transfer Learning) confirm that you should indeed set n_out to the number of classes (the other thread suggested n_out=dls.c).
Thanks for highlighting that these models don’t have pretrained weights. I now tried to confirm which networks actually have pretrained weights and I could not figure out whether there’s an overview location (“model zoo”) for that. I followed the source code and found where the pretrained models get loaded from some Amazon cloud storage, but presumably I’m overlooking something obvious here, or am I not?