Did you have a look at `eig_vals`? I think the strange results when using `pick_ori='optimal'` may be caused by this. In the free orientation solution we discard small eigenvalues (`pinv(Ck, 0.1)`) whereas here we explicitly use the direction of the smallest one. For MEG, isn't it the case that `Ck` only has 2 non-zero eigenvalues as it essentially doesn't see the radial component?