Changing an 11 stage pump to 6 or 8 stages?

I have an 11 stage, 2 hp, 3 phase booster pump [freestanding submersible type] that wants to run about 40 GPM at 90 PSI, up to 180 PSI.

What I need is more GPM at a lower pressure, perhaps 20 GPM at 60 PSI.

It has a 50 psi INFEED and pumping against about a 100 foot head. It wants more head, so its obviously the wrong pump for the app.

Could I remove stages and add a spacer, or ? Any thoughts? throttle it back?

A CSV would make it hold 60 PSI steady and deliver any flow rate you need down to 1 GPM. It doesn't hurt to remove 3 or 5 impellers and leave the diffusers blank. But you will need spacers to fill the space on the shaft where the impellers came off. Spacers are impossible to find. You will need to grind off the impellers and leave the hub only to use as a spacer. Not a fun job, but it can be done.