-
Get an 11 speed Shimano cassette, remove one of the middle sprockets 16/17 AND the spacer.
Take the spare spacer and put it onto the freehub before fitting the rest of the cassette (minus the 16t or 17t) and it will work fine, just don't shift into the "missing" gear.
This is what I do on my Lemond Revolution and I don't have to mess about with the indexing at all when swapping between wheels and it.
-
That's basically what I did above (https://thehippy.net/blog/raltech-disc-cover-11-speed-cassette-spacing/) to get around the Raltech covers fouling the biggest cog on 11spd.
My bike has an 11sp shimano drivetrain, but my turbo wheel has a 10sp shimano freehub and cassette.
What is the simplest and cheapest solution to get them to play nicely together?