JM, You can just use ^ to put the fingering above or _ to put it below. If the voice will always be the lower voice (as in your left-hand piano example) this works well. BUT it doesn't allow you to choose the orientation (top or bottom) after inputting the notes. Note that using - (as in your example) allows LilyPond to put the fingering wherever it likes.
%%% a,_3 e_1 a, e | % 2 %%% Hope this helps, Greg Hello folks, > In the attached score, I’ve had to create artificial one-note chords such > as <a,-3> for the down fingering orientation to be taken into account: > \set fingeringOrientations = #'(down) > <a,-3>4 <e-1> a, e | % 2 > I didn’t find other ways to achieve this result in the docs. > Would it be reasonable and feasible to apply such fingering orientation at > the voice level? > Thanks for your help! > JM