As far as the second question I'm not sure yet. I have only seen it go one way. So long as it is able to move and reset without slapping anything or fatiguing the sear spring do to increased speed/changing the point of contact thus the actuation, I don't see a potential issue. But I'd have to mess with it or see how it interacted. Which will be difficult as you know having changed the parts yourself how small of a space we're talking about here, you have to really watch it, and the contact points are obscured because the action happens below all of the moving parts as you also know. But you'll know if it messes up the Sear spring because you'll get hammer follow if it does. If it smacks it out of line or fatigues it, that's what happens. IT happened to Todd Green in his LEM, I forget where in the test though.
As for the second part of the question, HK likes to be complicated but a smooth symphony of parts working together. I initially thought it was the trigger bar that made the whole interaction sloppy but it appears to be catch and that part of the sear group. A lot of people have made micro adjustments in the trigger feel with the light FPB and the Nickel coated sear spring. It would be easier to show you internally with a pistol apart. But if you take your slide off and hold the hammer with your thumb. You can reset the action by pressing the top part of the disconnector towards the right hand side with the pistol facing away from you. The part all the way towards the frame. That part has the eyelet sticking out that you can see and moves the most in the process with the pistol apart, it pretty much is completely responsible for starting to reset everything when the slide moves. The rest of the parts interface with it to get going. So I thought that eyelet which appeared to be larger was also the culprit. But The part they've engineered here controls most of the movement and is responsible for resetting the sear. The catch and control lever (which is the part Grayguns is providing) moves the sear around to interface with the sear spring located in the magazine well of the frame. By changing the geometry of the control lever or whatever they did, I have look at it more closely when I get it and compare the parts side by side.... but my guess is they changed the length of one of the arms which would shorten the overall travel of the sear mechanism allowing it to reset in the same physical space but change the rate/distance in which it does it. They also do that without chopping any springs which is nice because that was a Bill Springfield maneuver and when it came time to replace anything you'd undo his work. Plus the chopped springs caused reliability issues and messed with the system. I really don't like chopped springs.
Grayguns did it right, this is the part you want to change to effectively make this happen without messing with anything else. It also doesn't move that much, you can see it move when you mess with the trigger when the gun is apart. It maybe moves 10-15 degrees, possibly less than that I was being generous. Although I'm not sure how only coating the control lever will interact with the rest of the non-coated parts in the system. We'll see and I can't wait to get my hands on it. I'll do an install and comparison video with as much nerdy detail as possible.