Regarding precision, I found that the small rotaries on my x56 throttle have just enough precision to work well for tuning. I frequently find myself making single "tick" adjustments, but the ticks are small enough to do the job and the setting is stable over time. I think those are the least precise of the four rotaries on that model.
I think it probably depends on how a HOTAS implements the rotary control. It seems many of them have too much resolution, rather than too little. I'll need to get into the technical aspects for that to make sense.
A USB game-pad controller provides up to six "analogue" controls: LX, LY, LZ, RX, RY, RZ. Each of these controls can have any range. The game-pad specifies the minimum and maximum range of the numbers it will be providing. It may, for example, say that it will supply numbers in the range 0-1000. The game software then has to map those numbers onto the thing that the control is controlling.
There are two sorts of control: analogue and digital. Analogue controls are cheap (a few pence) and digital controls are expensive (a few pounds to many pounds). With an analogue control the gamepad reads a voltage off the control and converts that to the number range it has said it will be using. With a digital control it will get signals when it is rotated up or down. It adds these numbers to a running total to produce the current position of the control. It follows that you can't move it by less than one position and that limits the practical resolution because if you want a control with 1000 positions per revolution you will be spending £50 or more for it. The result is that you have to spin the control to get anywhere.
An analogue control on the other hand has a fixed range of movement -- generally 270 degrees -- but reading an analogue voltage is not a precise activity. There will be noise in the system which generally means that you have to take great care if you want more than about three digits of accuracy. Even with three digits you will see the effects of noise -- the position of the joystick will jump around a little. There are ways to mitigate this in both hardware and software but they will limit either the resolution or the responsiveness of the control. As a rule of thumb, a range of 0-255 should be stable enough but 0-16383 would always be unstable. 0-1000 is probably acceptable on an expensive enough joystick. There is also a question whether the human fingers can control with that kind of accuracy.
It's possible to implement a range of 0-16386 with an analogue control that you've given a resolution of 0-256, simply by multiplying by 64 but that means the gamepad will be producing numbers with holes in. If you move the stick by a tiniest amount the number will jump by 64. This might confuse the game software.
There are two sorts of control: analogue and digital. Analogue controls are cheap (a few pence) and digital controls are expensive (a few pounds to many pounds). With an analogue control the gamepad reads a voltage off the control and converts that to the number range it has said it will be using. With a digital control it will get signals when it is rotated up or down. It adds these numbers to a running total to produce the current position of the control. It follows that you can't move it by less than one position and that limits the practical resolution because if you want a control with 1000 positions per revolution you will be spending £50 or more for it. The result is that you have to spin the control to get anywhere.
An analogue control on the other hand has a fixed range of movement -- generally 270 degrees -- but reading an analogue voltage is not a precise activity. There will be noise in the system which generally means that you have to take great care if you want more than about three digits of accuracy. Even with three digits you will see the effects of noise -- the position of the joystick will jump around a little. There are ways to mitigate this in both hardware and software but they will limit either the resolution or the responsiveness of the control. As a rule of thumb, a range of 0-255 should be stable enough but 0-16383 would always be unstable. 0-1000 is probably acceptable on an expensive enough joystick. There is also a question whether the human fingers can control with that kind of accuracy.
It's possible to implement a range of 0-16386 with an analogue control that you've given a resolution of 0-256, simply by multiplying by 64 but that means the gamepad will be producing numbers with holes in. If you move the stick by a tiniest amount the number will jump by 64. This might confuse the game software.
The FSS tuning control I built uses a digital control with a range of 0-255. It works very well with the FSS. One detent on the control is often the difference between being in tune and being out of tune, but it never skips over the tuned position. On the other hand my cheap HOTAS joystick (Thrustmaster USB) which I think has a range of 0-16383, is very fiddly to use. You have to get the positioning spot on and it tends to jump around. But the control itself isn't that bad; it doesn't jump around by 64 so it should be as stable as a control with a 0-255 range, probably even 0-1000. I believe that ED adapts the tuning requirements according to the resolution advertised by the control. As a result it is easier to tune with a low resolution control than with a high resolution control.