With the release being very likely half a day away, would it be smart to install the latest beta now to avoid the download cue? Would my beta then get a little patch tonight, or would I still have to download/reinstall a public version anyway?
I think it's doubtful Apple will just release an "patch" in the same manner as releasing an OS X 10.x.x update. They'll most likely make a clean break between the betas and official release. But then again, maybe the latest developer preview / public beta = GM.
In any case I'd just wait for the official release.
Yes, I did the same thing. if required, Apple will provide an update of the beta to the final version, so there will be no difference between that and the version they release as final.