Stall speed for the K21 is in the high 30s
I'm probably being too cautious, then... it was dead calm (or nearly) and of course when we did turn final at 50k the thing was solid as a rock, no lack of authority, no buffet, etc - but I was rather keenly aware of how good my speed control had to be. And of how finely controlled my round-out - er - isn't yet.
Thanks all, interesting stuff. And cats_five, let me know who you are on Thursday