I have 4 of them now that I use for specific purposes. All but one were purchased off evilbay and all came with both Lg and Sm cylinders. I fully agree they take getting used to as far as stroke and rhythm. It takes quite a bit of use or practice to develop a repeatable action and hit your intended charge, but certainly not impossible.
I found that the smaller the charges the easier to miss the mark with in most cases. I have the small drum in the one set up on my 4x4 press. Probably the lightest charges I throw is around 5.5 to 6grs of Unique for my 45ACp. I have found some differing charges while throwing it but not by much. Due to the loads I am shooting with the cast boolits, I don't sweat what little it is off. With most of my other pistol rounds I use AA powders which flow through like water. With the press mounted measure there is really little you can do to influence the powder. It settles as you load and thats about it. I do tap the sides a bit before starting but once you start cranking out rounds it is mostly up to gravity, and the baffle.
The ones I use bench mounted I can easily keep within a tenth or so of my intended target load with either stick or ball powders. Like mentioned however it does take knowing how to tap on the up stroke and down stroke to hit those settings repeatably. This said "IF" I am loading to the top end of anything, I will simply dump in my measuring pan and weigh the charges individually. I do this so rarely however that it is a non issue. I usually pick loads which are in the middle and when I work them up I am throwing the charges anyway, so I get very close to or exact performance time and time again.
I really like to use mine to work up loads while at the range. Simply take the powders and check the settings on the stem with my scale then while at the range simply stay within those parameters while working from the low end up in 1/4 turn increments. This not only makes it easier to work with while at the range but is easy to repeat once at how to get the exact weight. Simply use the number on the stem plus the actual turns and your done. A lot of my load notes are listed as the powder used and 3+2 1/2 turns or similar.
Mike / TX