SLX GS (short/medium cage) I think the cheapest, unless theres a short cage deore I never found when I looked
I’ve got one on my 2×9 main bike. A bit heavier than an XT but I’m not worried about bending an aluminium cage on an XT with a steel SLX
I’ve heard of others and myself bent an alu. cage XT on a hire bike before, but never my own XT one.
For my XC 1×9 I used a long cage (thats what I had) and chopped the chain to suit chainring/casette combo, such that the mech cage is nearly flat when in biggest sprocker and about straight down when in smallest sprocket
Isn’t too bad on chainslap though as I use it for less ‘agro’ trails (main FS is for that) it doesn’t get a fair test
Up front using only a top guide is more of a problem, how much of that is because its a superstar one I don’t know. A front mech with the low stop wound right in ime has worked better for the short time I used it