Why? He already has an 11t cog on his other cassette.
FWIW, I have two sets of rear wheels, both disc, both using the same brand of hub and rotor. One is my "Upstate" cassette (10-36 12spd SRAM) and the other is my "LowCountry" cassette (10-30) No issue at all with rotor alignment. I use the same chain and just adjust the B screw with the tool. I have never had to fiddle with chain alignment on the RD.