For over a year now, I have been developing an add on adapter for the RH stick on a ST16/ST16s base station, which is simple to install, use and remove. It has 6 discrete positions for speed adustment from 0 to full (in pitch, or roll or combination of both). No change is required to the stick, simply place it over the stick into the well and place the "compass ring" over as "retainer". Then, any position of the stick can be instantly increased or reduced by moving the slider a notch or more and can be quickly removed in case of emergency by simply lifting out of the well by the dial handle.
The device allows the pilot to set a certain speed and trajectory with the RH stick and "continuously steer the aircraft" or leave it set to one direction (forward, backward, left or right or any combination). This allows more freedom to focus on the LH stick for Alt and Yaw and to modify the camera tilt/yaw. It makes "crane" video shots smooth and controllable. You can do manual POI shots and "inside-out POI shots" and will discover lots of other uses.
I will try to get a video up today showing it in use. This is probably not for a rookie pilot, and of course I am not liable for any damage due to misuse or pilot error.
I have a few of these that I 3D printed and if you are interested send me a private message about how to aquire one. There is a considerable amount of post-printing work to finish one of these and test it for fit and function, so after the first few are gone, after that there would be a delay to build more - possibly a week after ordering. Here are a few pics - works on the st16/16s, so H480, H520, H+, H920+ (Have not tried it for fit on the ST24, but might work if the RH stick well is the same)