If you record at 16 bits of depth you are pretty much automatically forcing your engineer to choose between quality and range when they are normalizing the recording.
The most important rule of audio recording is "always be ready to roll tape". What the engineer does is of little consequence compared to the talent. Don't ever fuck up a keeper take.
Recording with some extra bits means that even if your gain staging was bad, you just get some extra uncorrelated noise, not correlated quantization distortion.
As for whether this stuff is perceptible, there are two issues at play. First, differences which are not perceptible during production can result in a perceptible difference in the final product. This is easiest to understand with a visual analogy: if you have inadequate resolution of an image during processing, the end result may be slightly defocused and smeared.
Second, as I described elsethread, quantization distortion is a particularly pernicious form of degradation, poisonous in small amounts. https://www.youtube.com/watch?v=8KkS4NSv-0M It is hard to listen for it during production, so we defend against it by giving ourselves lots and lots of headroom.
As for how much safety margin is "enough" during initial capture... We're looking at a stark choice between either 2 or 3 bytes per sample. 2 bytes seems to be borderline, while 3 bytes seems to be plenty. It would be hard to quantify a safety margin more precisely than that.
If we want the best quality end product, free from low-res artifacting, we need to preserve an excess of resolution all the way through production until the final export. Exactly how headroom much is enough? Enough that artifacts arising from insufficient resolution are not perceivable in the end product.
The studio I used to work at was one of the first ADAT studios back in the 90s, and they did a lot of rock. One of the ways they got past the limitations of the medium was to compress and limit to tape. You generally don't want to do that unless you have tons of time to set up and get it right (a la Rudy Van Gelder), which was not in most budgets. But it worked well enough and the ADAT recordings out of this studio sounded way better than most.
Mercifully storage has gotten cheaper in the decades since and you really shouldn't capture to 16 bits any more.