Just trying to increase your good eggs for best % of hatch I see you have your mind made up. You asked and I gave you my best option if it were my eggs I would go with the norm for all eggs but 1. Giving the best chance for the 22 most important eggs to hatch.
If that particular egg is that much more important to you than the other eggs. Just swap that single egg in turner and do the limited turn on one of the lesser important eggs. Giving your single egg a better chance if it that important to you, that would be my option along with regular lockdown...
Yes, as you stated single egg is not getting best attention and its only 1 egg compared to 22 that are being turned correctly and in better circumstances. And 2 days early will not harm your single egg. Also, higher temps will not catch up your single egg as temp will affect all eggs equally.