We taught a selective radial scan on SAR which worked well for over water hovering when references can be poor.
It concentrated on the hover attitude and assumes you have a visual horizon. Looking out of the front gives you attitude, heading, lateral drift and some height information.
Then scan down through the AI and compass and rad alt to confirm what your visual references are telling you is correct and then a glance to the side to assess longitudinal drift.
Do this with minimal head movement if possible as that can disorientate you.
The scan can be adapted for NVG but requires more head movement.
You can do this IMC over the water using the AI and a doppler meter if you have one - or buy a modern SAR helicopter with auto hover.
Using the relationship between an object in the near to middle distance and another object further away can give excellent height references.