I use LR6 most of the time. NR set at 25 in the present case; sharpening is mostly left at its standard value (25). Sharpness is well preserved despite the NR. These two lenses (105/2.5 and Zeiss 35/2) are my best lenses for shooting organs, together with the 300 PF for details (set at 1/30s with VR).
The Zeiss displays, by far, the best behaviour with backlighting. The Nikkor is not that good under such circumstances, but it does not often matter as the framing is much tighter, and windows are more easily avoided. Also, 105 is not too long a FL, so it remains possible to shoot at 1/60s (series of 2-3 shots preferrably) and keep the ISO within reasonable boundaries. Even better, the widest aperture (2.5) delivers enough sharpness and contrast, so it can be used when the subject is reasonably flat.
I have not tested the 105/2.8 VR under such circumstances, maybe it would be a good alternative.
In any case, artificial lighting should be avoided whenever possible. Organ front pipes, especially the shiny ones, do not look appealing when lit by usual lamps.