I found these lovely potentiometer knobs (https://no.mouser.com/datasheet/2/26/aluminum_Knobs-348847-1158343.pdf), but I'm not sure what type of potentiometer shaft types they are supposed to fit. I've specifically bought the KB-series which has two fastening screws, each 120 degrees apart and 120 degrees from the marker. When using a flatted/D-type shaft, the fastening screw has to be 180 degrees from the marker to make the marker point at the current pot position, not 120 degrees. Is it meant to fit one of those knurled type shafts?
Your Mouser link is an ample assortment of knobs, with various dimensions and styles. Some have the marker 90 or 60 or 180 degrees from a set-screw.
I think it's up to us to determine which arrangement is suitable. We have to make sure there is clearance for working with a screwdriver or allen wrench.
Where you have 2 set-screws, it's well suited to smooth shafts, uniformly circular shafts. It needs the extra gripping power of 2 screws.