Just done some experiments. For instance, if you want to know if William Bradford is 5-star, you can go to the WikiTree+ Search form and select Text Search, and type in "5stars WikiTree-9" and get a list of the 5-stars managed by the Mayflower project account. Then scan the list.
If it's a long list, you can then narrow it down by adding another keyword, eg
5stars WikiTree-9 William
5stars WikiTree-9 Bradford
5stars WikiTree-9 Austerfield
5stars WikiTree-9 24
(24 is the numerical part of the WikiTree-ID)
To cover all project accounts together, you can say
5stars ProjectManaged Austerfield
For profiles that aren't project managed, use the WikiTree-ID of the PM.
For profiles without PMs, say Orphan.
Or you can skip the PM altogether, eg
5stars Austerfield
But searching for the profile's WikiTree-ID, Bradford-24, doesn't seem to work.