Coroutines end time sketchpads

Hi

I am struggling with the co routine options and specific end times for sketchpads.

I'm looking to program an experiment where a stimulus is shown for 500 ms together with the two answer options. The two answer options need to remain visible for 5000 ms (including the 500 ms it is already seen during stimulus presentation) or until key press. The answer is given by key press, and the key board response needs to be available for the full 5 seconds, so both during the first 500 ms when the stimulus and answer options are presented, and during the last 4500 ms where only the answer options are seen.

So I tried a co routine with two sketchpads and a keyboard response. The two sketchpads are one with the stimulus, and the other with the two answer options. Although the experiment runs, the stimulus is flashed very fast, and I can't seem to time the end time for the stimulus at 500 ms.

I just reread the instructions with co routines (https://osdoc.cogsci.nl/3.2/manual/structure/coroutines/) and found that "Each item has a Start time. Most items also have an End time. The end time does not apply to one-shot items; for example, sketchpads show a display and terminate immediately, so they have no end time.". Does that mean this approach won't work for me? Or am I complicating it unnecessarily? What is the best way to go about this?

TIA!