Hearing what a great capsule does in the sibilants and spitty regions is not a problem for me.
That alone, in conjunction with monitoring over your own headphones whose sound you are familiar with, is a fantastic start to evaluate sibilance and mid-range congestion of a mic.
The larger question you ask me is not quite as straight-forward to answer.
It seems that my constant badgering Neumann to at least losen the backplate assembly screws back to the torque they used to apply has, at least for the moment, been responded to, and the last five 2021-made capsules I tested were torqued again to the original 1960s torque (there are no 2022-made capsules out as of yet, as far as I have seen).
That reversal back into healthy assembly-screw-torque-territory has not extended to diaphragm tensioning, though it has audibly helped the overall frequency balance a bit. I still observe that
too many of the K870/87/67 capsules made in the last decade lack proper, relaxed representation of the lower octaves of the capsule's transmission range, i.e. their mid-forward and slightly or severely congested response in the range that causes sibilance is objectionable to my ears.
But, I have to emphasize once more, this mid-range prominence and bass starvation is not consistent, but varies widely from capsule to capsule and capsule side to capsule side. I continue to occasionally encounter perfectly frequency-balanced specimens of these capsules.