Will a newer Shimano series cassette be easily interchangeable? I'm trying to create two wheelsets that I can quickly swap out on the same bike for different conditions.  My existing set has a Shimano 105 5800 series 11 speed cassette.  They discontinued that so you pretty much can only find the newer Shimano 105 7000 series 11 speed cassette.  

While reading a review of the newer series, it was mentioned that:


  It's designed to also fit a mountain bike wheel, so you need the optional spacer if you're fitting it to an 11-speed road wheelset.


My question is, will the spacer requirement on the new cassette with my road bike force me to mess with my rear derailleur indexing/etc. when I swap the wheelset/cassette?
The spacer is required for 11-34 cassette only, same story as CS-R8000 11-34. The 34t cog hangs over freehub body, which allows to use the good old 8-10 speed HG freehub body. For a note, Shimano MTB 11 speed cassettes do not require 11-speed specific freehub body either.




  My question is, will the spacer requirement on the new cassette with
  my road bike force me to mess with my rear derailleur indexing/etc.
  when I swap the wheelset/cassette?


To be honest, I did not run this cassette, but it would make no sense to change offset just because it uses a carrier spider instead of cogs riveted together. At worst, you'd have to put a thin spacer under the cassette when swapping it between 11-34 and smaller range options like 11-28.