Here is what I'm coming up with so far:
There are the ones they say 3RL - 9RL which are Round Liners. They are very tight together and it appears that the 3=3 needles grouped together in a circle, 5 = 5 needles, etc.
Then the 3RS-9RS which are Round Shade - same grouping but they are spread further apart and have a longer needle
so seems to give a softer and wider scratch. So far these rounds are my favorite!
Then the flats are same type of thing with the 3 = 3 needles, etc.
What I do not have down yet is how to find the flats with only one row and then the flats that have 2 rows. But both styles exist but the numbering configuration probably adjusts to with a single row or double row - I'm hypothesizing.
They are wonderfully sharp and if you keep blowing the ink and clay out that last for quite a long time - I have not given one up yet for a new one in fact.
Definately turn, twist, change angle and push, pull, sweep and for the flats with double rows use the edges at 90 degrees from what you would naturally do!
These things are so versatile!!!!! I LOVE them! I working on developing and kind of "under-fur" technique. Once I get it down I'll post some stages. I have to take a photo of a couple new tools I've come across and post those as well. I'm intrigued by Ann's newest toy. Scratchy toys are so much fun
Oh ya - If you have a good pair of wire cutters you can snip the tat needle
within about 1/4in of the weld then stick that in a Leadholder or Clutch Pencil. 2mm seem to work really well. You have to stick it in far enough for the weld to be the part that catches in the clutch teeth but if you experiment you will find what works. I have 3 lead holders all the same brand and size but all 3 tat needles are in at different lengths due to the variety of needles I guess.
Good luck and have tons of fun - they do stab the board pretty easy if you have a coffee spaz ;P not that I would know from experience - heheheh