2022 Triumph Bonneville Speedmaster
I had a pro suspension shop who is regarded as top-notch in the SF Bay area (Super Plush) do the work and they were pretty confused and it was a bit of a nightmare. Having to do machining is pretty common in fork cart kits, but the difference between Matris and Nitron is that Nitron lays out what is required of the install, whereas Matris had no instructions for the modifications.Sorry for the late reply, I had Monkey Moto in Argyle, TX fit the emulators when I ran into the too long bolt problem. They indicated the same thing you describe, the kit wasn't really made for the DIY mechanic and needed a professional touch.
I put in some Nitron fork carts into another bike recently (Ninja 400) and while the instructions weren't perfect, they did lay out the modifications needed, such as latheing and -- I was able to actually get a hold of people there who were able to clarify what was missing from the instructions (they had updated the fork cap design so the instructions for the lock nut were out of date).
My experience with Matris was that they first ignored me, then lied to me, then claimed I was the one lying. They are maintaining despite my first hand experience, and my photo and video evidence, that the kit is "drop in" with no modifications needed to any OEM parts, which is plainly laughable, and which is why -- unless they change their tune -- I'm personally never buying any Matris kit of any type again, nor will I recommend them to anyone else either.