23mm is where it is at!
This is my first of the new Muhle plant based STF knots. I cannot say if I like it as much as the original STF? It definitely benefits from some break in time. I have maybe 15 shaves on it and it has improved greatly. To be fair, it was never bad. I find the original STF is good to go in maybe 5 shaves. The plant based version does take slightly (barely) longer to dry. It still gives up lather well. Minimal loading still gets me 3 passes and a little cleanup with little to no residual lather in the knot... perfect. All in all it is good. About the only con is petty and I think does not affect performance. When you squeeze the knot, the fibres kind of... grate?... grind?... rub?... against each other. Different, but not a problem. Also the knot is a little shaggy, a little non uniform in length, with some outer fibers being longer than the central fibers. Not a problem, just an observation.
I will say ABSOLUTELY GET THE EXTRA DENSE VARIANT!
As always Andrew is a pleasure to deal with!