About U-joints...

Hmmmmmmmmmmmmmmmmmmm
"Some between the cups" is normal,but .008 seems to indicate that the cups could be closer together, or the cross, a little wider. Depending on which method your yoke uses to locate the cups, this cannot usually be changed. Greasing it, of course, filled the internal gaps with grease which "cured" it. Of course soon enough the play will be back.
So, what to do about it? IDK.
If your yoke has cup-stops and straps, I guess theres nothing that can be successfully done,short of shimming the stops.But I fear the shims will fly out, as there is nothing to keep them in and the straps do not have a whole lot of clamping force.
If the cup-stopping is done by snaprings, I suppose you could inspect them for flatness, and thickness, and try to hunt up some thicker ones.I doubt you'll find any tho.....
But if you have the U-bolt type of cup retainers, they clamp pretty hard.I suppose you could shim the outside of the cups on those before securing the U-bolts. And then pulling the shims out.
All-in-all, IDK if there is much you can do.
Modern U-joints are well machined, and I bet you could measure a hundred of them and not find much variation among them.
Hmmmmmmmmmmmmmmmmmmmmm