Well, I've had this vintage Rooney butterscotch in my den for approximately a year. When I bought it, the knot was in rough shape and fell out in pieces. It sat on my shelf waiting patiently to one day be used again. You can see it here: When moving my brushes around I decide to measure the knot hole and thought it to be close to the Plisson cup size and gave myself the permission to marry the two. So, here is the result.
Could someone please tell me if there are there any synthetic knots that have backbone? I tried an Omega and loathed it. I would try synthetic again but I am a head latherer so floppy just does not cut it.