I live in a parallel but dissimilar universe, in which the GS pedal works on 18s and 20s, and in which the difference in sound between centric and eccentric hits is noticeable but of no concern. I use the same beater adjustment on both 18 and 22. I don't use full extension, obviously, but did some testing and discovered that once the beater is off center, there is a huge amount of head surface where the sound changes very little before it changes again, near the outer edge.
The beater, of course, is not centerable - a new word, I know - by design. The center is taken up by the pedal strap arrangement, and the beater is mounted to the right of that.
I did cut down one beater shaft to bring the beater further inboard, but there was no too much cost in feel - with that, I agree.
Recording and miking - well, we all know how that works out, so what's the difference. But live, my kicks sound beautiful to my ears.
As to position, the beater hits just below the R on the 20, which does not seem extreme. If there was ever a problem in feel with the beater adjusted to that height, it has long since passed.