To me that doesn’t look like it should work.
^^^So validating 
I just tried setMarkerSize in PsychoPy and it doesn’t like that. FWIW, the solution for changing the slider size in PsychoPy came from @dvbridges here:
Slider: Making the dot size smaller without changing overall slider size - Builder - PsychoPy
Neither PsychoPy nor Pavlovia liked setMarkerSize. I reverted back to marker.size in PsychoPy and wrote the setMarkerSize in my JS code.
I got this error on Pavlovia:
TypeError: comfort_ldt.setMarkerSize is not a function
I’ve uploaded my PsychoPy experiment, if that’s helpful
story_list.xlsx (7.9 KB) storyX.xlsx (8.4 KB) pilotProcedure.psyexp (89.9 KB) storyY.xlsx (8.4 KB) ldt_trials.xlsx (9.8 KB)