I would guess that they are uncommon. The Colchester lathes themselves seem to be.
I'm not familiar with the Duplomatic turret or its holders. But if they are functionally similar to the Aloris style holders, the parting would be one holder. And the other three types could all be handled with a #2 Turning and Boring, if your threading tool is like either a turning tool or a boring bar (for ID). So you could get by with two. At least for starters. However, pretty soon you are going to realize that for convenience you are going to need several equivalent to either #1 or #2. I have an AXA and if I counted right, currently have about 15 of the #1 or #2, most with a cutter already installed and set set up on center in them.
So just let it run. If you check it one day and find it off the screen, just do a "bump" or "Back To Top" to bring it back on the screen. If I happen to see it in a few weeks and see that the actual first post is now off the bottom, I'll delete all of the bumps except for the most recent. If you ever feel that you have enough, just add a post to say so and eventually I or someone will edit the title so that it begins with *** Found ***.
