Just about to mate a XTR double chainring with an 11-36 XT cassette on a hard tail. Will a XT type 2 rear mech with medium length cage cut the mustard?

I think a medium has a max capacity of 36t.

Your cassette has a range of 25t, so it depends on the difference between your chainrings. 11 or less and you should be fine.

GB

I am pretty sure I have that set up on my bike. XT 40-28 chainset, 11-36 cassette and XTR Shadow+ medium length mech. It all works fine. I am sure I checked out the numbers when I built it up and it was within Shimano’s limits.

24-36 crank, 11-36 cassette, XT Shadow Plus medium cage (M786 GS) works fine for me.

Despite threats by pestilence, plague and famine, I have run a medium cage mech with a full 3 x 9 set up (22t to 44t front, 11-32 rear) with no problems.

I tend not to use the extreme ratio’s though (big / big & small / small) but you won’t be doing that anyway? 😉