Hi Ed

I think I must disagree,
I am sure that the design of lenses for enlargers are not built with depth of field in mind. The are designed to be focused sharp along a flat field which is the enlarger easal.
I have never corrected un - sharp edges of a print by closing down, alignment of the lensboard negative stage and easal is the only way that I am aware of getting sharp edge to edge.
As well try putting a lith negative of very small sharp type into your enlarger and project , and then start wide open , middle f stop, and very closed down.
adjust the density so that each print equal.
You * will * find that some of the prints are much sharper and ledgible to read.
In my past , I did a lot of multiple exposing of images and type onto photographic paper and film and I know that selection of apeture for the type was critical.
This may be a simple test to do and I think that it does indicate some fstops on an *enlarging lens * are better than others.
This simple test can also answer the debate whether you should have white walls or black walls surrounding ones enlarger.
Granted when we did these test we were making 8ft murals and the room we worked in was large. We found the type to be sharper with black on the walls not white.