I'm happy with my setup you've seen my one only saw your post today on fula's thread sorry man, only thing I'd change is probably making up bottom adapter plate as my linkage has hit frame on bad bump or may grind bit more out of frame. also hasn't had much of field test as electrics played up on bike and only just got stupid thing sorted now, no high speed testing done yet. So maybe someone on here will give better insight as my one not really tested I'm more of a manufacture problem, test, improve
I have the k4 arm which is same as k1 I think looks similar, used 2mm washer too in swingarm bearing dust covers to get spacing right.
k2 linkage and wheels, adjustable dogbones and adjustable top mount bracket (sits high have custom subframe so not sure if will work with stock setup) which is recommended as I'm still tinkering with my setup still not right.and my shock is one that fitted the stock 750 size, hagon with a different spring rate.