I would be happy to pay monthly or yearly to get better functionality.

So far my experience with paid vs free relays hasn't made a noticable difference.

I find the selection of which relays to use and exlcude a confusing process(though I appreciate the descriptions now included in amethyst). 

When adjusting relays I generally just troubleshoot by fiddling randomly until something changes and then leave it alone. I would like to better understand how to optimize relays.