I'm a Lumberjack.
Interesting maybe I need to look at the c5My 620 is from around 1.5 years ago, so probably similar to yours. It's an outstanding brush, the only real complaint I have is the bristles are dyed with the fake stripe. What's interesting is the bristles fan out into a cone shape so the knot seems larger than 22mm. It looks almost the same size as the C5 with the 24mm x 50mm knot. The C5 is just more dense and plush. Honestly, I like both of them. The C5 feels almost like a plusher version of the 610. It took a while to break in, but it is becoming a favorite now.