I have three (short) needles are something like, K22, K23 and K28. The "longer" needle I have just purchased is a K59 (I think).
I don't know if I need a longer needle, I was more surprised that a longer needle existed (and with a different number of grooves).
There is a hint in the explanation of needle K33, which translates as "
differs from K27 to have a length of 70.5", which might indicate that longer needles have a place in the range.
98 needles. You can find the needle chart here (Thanks Eurocarb).
https://www.dellorto.co.uk/wp-content/uploads/2015/06/K-U-Needle-charts.pdfI printed it off, and the similar chart for X needles, and laminated them back-to-back.