does that mean that I should delete and/or draft any of the WPSP that I’m no longer using?
The stylesheet will only load once, regardless of how many WPSP lists you have on your website. Where possible, we load CSS specific to each list directly above the list in the HTML. This makes it so less CSS is added site-wide.
As for your custom CSS, you can use a plugin like “Simple CSS” to add it only on specific pages. That way your CSS isn’t loading where it doesn’t need to.
Let me know if that makes sense or not 🙂