Yes, you can change the weight in the M890 head. It comes with an 8 gram weight, so you can add up to 6 grams (14 gram weight), which would get you back 3 swing weight points. Not sure why I didn’t mention that before. I think starting with shortening by 1″ is a good place to start.
You can cut 2″ off the butt end, but be aware the swing weight will go down a lot and it may play a little softer. I definitely like the idea for most players of playing a shorter driver length, especially when in most cases it produces more sloid contact, more consistency and usually does not reduce distance that much. I might suggest cutting a little less than 2″ off to start to see how it does. You can always cut more. You can use lead tape or other methods to increase the head weight after cutting if you feel you need to to maintain the head feel at the shorter length.