I ended up getting a Franklin Electric pump from a local well digger. I replaced the pump and the wire (it was worn through in at least one spot).
Sucker is pumping like crazy now.
I'm getting somewhere around 10-13 GPM from the drain valve/water hose in the basement.
I reset the pressure switch back to 40-60 PSI, adjusted the air pressure in the pressure tank, and adjusted the CSV to a steady 50 PSI (at 2-3 GPM flow).
Everything seems to be working as expected.
Thanks for your help!