I also don't think we need a beta phase. There would probably be only a minority of people who would test a beta release (or only the changes).
If there's some blocker bug, there's the possibility to release 3.9.3 ;-)
Announcing a target release date is a good idea. Or at least an "end of coding" date, so that everybody who plans to fix some major bug or implement a feature can prepare.
May 1st sounds ok, but maybe a little later is better (it's only 9 days until 1st May).