I wish I understood why a hypothetical 8gpm-1hp would not be good but an 8gpm-3/4hp would be.
8gpm-1hp would certainly not be as bad as 5gpm-1hp. Pump would be operating off the right side of the graph too often. 8gpm-3/4hp would stay in the efficient area more.
My own thoughts:
Does the pump deliver at least 2 gpm at 270 ft of head so the pump can shut off if the well is ready to run out of water, but can still fill a toilet tank or give you a glass of water?
Does the pump work a lot in the shaded part of the graph during long use activities? That's good.
Does the pump produce sufficient gpm at the 35 (I thought about saying 30 or 40) for your big longer use activities? I was thinking about something like irrigation, or backwashing a big iron filter. If the pump only produces 30 psi when regenerating that big iron filter, that is enough for that job. Nothing drastic happens if the pressure drops to 35 during irrigation, even if the cut-in is 40 or 45.
Does it mostly avoid > 10.5 for the 7 gpm pump and maybe 14.5 for the 10 gpm pump? Max water height and cut-in pressure will affect this. If that is a problem, you can add a flow regulating valve.
You should determine your static level. Most use something like a fishing bobber on strong fishing line. Don't leave anything in the well, so be sure the line is strong and the connection to the bobber is secure. Many pros use sonic depth sounders that send a sound (maybe ultrasonic) down and time how long it takes to bounce off of the water surface and return.