definition of proper fitting?
insert semi solid like material into your ear for fit. remove, have ear mold made from model. try finished earmold/hearing aid in soundproof room. subjectively determine quality of sound.
is there a problem? could it be the hearing aid? the mold? tinnitus?
the only objective measurement of the mold should be some devise that measures the bandwith & energy that is transmitted thru the mold up to the eardrum. energy in/energy out. I would think that type of test eqpt. is whats needed to quantify the output.
this approach could also be expanded to test the hearing aids also. If the necessary bandwidths of sound are being moved to the eardrum successfully. problem aint hardware.