With a 1 X, 44t front, I just went from an 11-34 11 speed to an 11-34 12 speed. I am using bar ends in friction mode, only had to change the cassette and chain, and adjust the limit screws on the rear dr. The main reason was pure curiosity, but also, I did not like the jump from 21t to 24t on the cassette. I bought a cheaper Sunshine cassette, now no 4 tooth gaps, and the first 3 tooth gap is 25 to 28: 11,12,13,15,17,19,21,23,25,28,31,34. I really like that progression, as I am kind of particular about being in the gear that is right for me. I have only done a short ride to make sure it is operating properly, and will be doing a normal 25 to35 mile ride, shortly. My investment in dollars was only $63, the removed 11 speed cassette and chain will be used on a different bike. Don't know that this helps the OP, but thought I would share my experience. In my search, it seems going to a wider range 12 speed cassette, one is limited as to choice of biggest cog.