My only steadfast rule on sharpening is that I always make sharpening the very last, final, nothing-else-left-to-do, step of my process before saving the DONE image file.
That's including sizing for whatever my final output will be. My final pixel dimensions for a large print size are much different from my final for a business card, which are different from my typical display size on the web, and I find that my final sharpening step changes with them, as far as the settings I use, and even then, it will vary from image to image, and may even include masking and so on, if I want to be very selective about what, exactly, I'm sharpening, and how much.
That said, I will even sharpen in a few steps; Sharpened to taste for one area, then sharpened even more for another, then sharpened to the max in yet another. It's not often that I go that far, but I don't limit myself. I also pay attention to halos and mask them out when I feel the need, leaving the surrounding detail tack sharp.
As an example of my sharpening process, my typical web output is 900 pixels on the longest side, and I work at 300 pixels per inch right up until I "save for web", which happens immediately following my sharpening process. So, I'm looking at my image resized to 900 on the longest side, and I choose "Smart Sharpen", Amount: 100%, Radius: 0.3, Remove: Lens Blur. That's my starting point for that size image, and I'll adjust from there if I feel I need to, usually just on the amount slider, rather than on the radius. Very often though, I'm done just by using my initial settings.
For large prints I'm making myself at 13" x 19", I find that I usually do the same thing, but up my Radius to about 1.3 px as my starting point.
I've never worked with PSE, so I don't know if it works the same or if you have "Smart Sharpen" or an equivalent, but maybe that can help give you some ideas anyway.