I'll ask Mark to take a look.

Most likely, a VFD motor could reduce your operating costs quite a bit. A 2HP pump, running full on, is way more circulation than you need for your pool, and is probably sized so it can also run the jets in your spa. There's a good chance you'll only gain the maximum from your refit if you ALSO optimize the valving and controls on your pool / spa switching.

Mark (and others) will be able to do a MUCH better job if you'll send photos, so they can see how your piping is laid out. If you'll send them to poolforum@gmail.com, I'll post them so all can see.