Thanks, Jon! Will shoot you a PM with my address.
With the nice weather today (hey, it's finally above freezing here!), did some more measurements, based up ckreef's feedback. If we want it to fit on the handles of the full charcoal basket and be centered under the rotisserie (I eyeballed it from the holes in the KK, since I don't actually have the basket yet!), the length should only be 17" long (i.e., need to cut off 1.25 inches). No need to trim the width. This is for a 23" KK, YMMV. Folks with the BB 32" shouldn't have any problems with the grate, as is out of the box.
I had forgotten that the KK isn't round, but teardrop shaped, so the widest part of the grill is NOT on the centerline, but slightly forward. This gave me another idea. If you don't want to cut it. If you place your basket splitter with the coals in the front half of the KK, then you should be able to cover almost all the coals and shield the rotisserie basket from direct fire.