No matter what the title says some knot have not exactly that number
TGN for example says that in a 22mm knot "Plug size is 21mm +/- .5mm"
So in a 24mm handle you have a 2.5mm gap
You have to put a lot of epoxy to fill it and maybe from close looks not so good.
+1+1+1+1I have found what Doryferon said to be VERY true in all the knots I've set. You will likely have an excessive gap if you attempt this setting you speak of. The top part of the knot may be closer to 23mm, but that still gives you a 1mm gap for which you would need more epoxy. Too little and it would be improperly seated, too much and it seeps out.