I won't even go beyond theory vs practicality on Willianson turns for boats our size.
For the life of me, I can't understand how someone would do a Williamson over a 90/270. Let alone a stop an back down or just stop and manuever to keep the person close. And there's more options that I long have forgotten.
If you lost sight of the MOB, statistics (at least my experience) show likely low probability of recovery. For MOBs in general, the vessel the MOB came off off is the likely recovery vessel.
If you lose sight of a MOB during a Williamson versus most other manuevers ,even though that is what the Wiiliamson is designed to overcome....it would be an unnecessary chance if you still had sight of the MOB..... and if you lose that person as far as I am concerned........
The main reason for the Williamson is to immediately kick the stern away from the MOB.... IIRC...returning to a reciprocal course too ....of course