Hi @alexlwhite,
My understanding is that locally run PsychoPy has access to most-any font you have saved on your computer, while Pavlovia has access to the fonts available on the participant’s browser. There is a list of web-safe fonts that should be correctly presented on most browsers. Maybe Courier used to be a web-safe font but has been replaced with Courier New?
Improving access to fonts on Pavlovia experiments is something the developers want to add, but in the meantime, the web-safe fonts are the best ones to try.
When I need strict control over the font of text stimuli, I prefer to make the stimuli in a separate software (such as Inkscape) then save my stimuli as images to use in the experiment. This gives me the most control over how stimuli are presented.
Hope that helps,
-shabkr