Okay I found the mistake.
net_trained.features[feature_idx-1].weight.data = weightConv[weight_flopk.view(-1,1),weight_flopk_prev.view(1,-1),:,:]
should slice my net. For example [128,64,3,3] to [64,32,3,3] with weight_flopk containing 64 indices and weight_flopk_prev containing 32, but gut a tensor of [64,64,3,3]. How would I select the dimensions correctly?