I used to use 11's on a bunch of guitars, when I was playing 6-7 shows a week. I
thought they sounded thicker, fatter, etc..
In later years, I began to learn that every guitar has its own character, and some really benefit from lighter strings. So, I moved down to 10's and 9's. I don't really miss the 11's (still have them on a Les Paul), and I find 9's are "zingyer / snappier / more sizzle / more cut through". Plus, I can dial in the fatness if I want.
I also believe EVH used 8's at one stage, so if it works for Ed! I also really like nickle, as opposed to standard steel, or coated.
The vast majority on this is on full locking trems. No nut work needed, but if the 11's gouged grooves into the locking clamps, you might need to change those to avoid thinnner strings sliding through the grooves. If using a standard nut you could apply some graphite to ensure the strings don't catch in the nut.
Also, 9's will exert several less kilos of pressure on the neck, so I would expect the nut end (therefore the action) to come up a bit. Some truss rod tweaking, trem spring tweaking, trem post tweaking would be needed to balance this out.
All much simpler than restringing a piano
