Too much play in RA (Sorry I didn't mean for it to rhyme.)

I have not had that problem before.  Usually the shaft fits into the cradle very tightly with no play at all.  I'm assuming the large setscrew  is allowing the shaft to pivot on the setscrew?

Is the shaft the correct size?   1" or 1 1/2" ?   If it was replaced, it may be too small.  Another thing that concerns me would be if the shaft was dropped or hammered out of the mount and the mushrooming of the end was "sanded out by the previous owner.   Of course the cradle could have been made with too much play when cast.

Many things.   Use a digital micrometer which part is too small.

I have used thin aluminum from an aluminum can to create shims for large gaps.  You could use that and a little jb-weld to get it tight.  You probably never have to remove the shaft from the cradle in your lifetime.