Okay, so now the pressure is on Fred. (grin)
My answer is I got lucky. My plate does not move and requires a bit more force to snap into place than I expected, but it does snap/click/pop rice krispies. That's about the only thing I've not seen referenced in these messages.
Another thought pops into my alleged mind. The Fleks people have in the past suggested that one can cut these plates with a fine tooth saw blade or suitable sharp tool.
The Flux Delta is 5.125 inches on an edge. My calculations and manipulations of drawing program indicate that results in a hexagon slightly more than 10" across at the widest point. I was able to rotate the hexagon I created within a 10" square, but the recesses of the Fleks 10" simple appear to intersect the edges of the hexagon:
The image above is to scale. I would expect that one could ignore the recesses in the Fleks 10" plate, or move up to the 12" plate and have no complications in cutting a clean hexagon.
This should eliminate any considerations with binding or movement, if the cuts are done accurately enough. There is a hexagonal plate that would also fit, at the same price, but it's also out of stock. There is little difference between cutting down a 12" square and cutting down a 10" hexagon in order to reach a nine point something hexagon, in my opinion.
I'm likely to order a 12" plate simply as an exercise and to eliminate the snap-in aspect of my current circular model.