I swear we must be doing almost identical builds!
I have a Holosun 510 (can't tell what model yours is?) on the way and already have the WML light.
Planning to get the cheek rest and probably the shell deflector (looks like you have the Primary Machine version?).
Undecided on a muzzle break yet. It would be as much for aesthetics as function. But also want to keep the gun as short and maneuverable as possible.
I need to decide on a grip and hand stop. I'm used to a default hold on my Mossberg 500, but the KSG is so stinking short that it feels awkward and definitely needs an angle or vertical grip. With the setup shown, can you reach the light switch with your hand on the grip? Ideally, I'd like to be able to operate my light without changing my grip.
Yup, we're nearly twins!
I'm using the Holosun 510C.
It is a PM deflector - I hate the shells hitting my arm. The deflector made me change the way I pick up the KSG so it doesn't bite into my wrist. It's a little in the way if I want to hold the gun one handed with the muzzle in the air and buttstock resting outside my arm. Occasionally it will deflect one to my chest. I'm sticking with it for now, but time will tell.
I got the kydex cheek rest recoil pad from MCARBO. I really like it. I slipped it over the end of the Hi-Tech decelerator pad thinking it will help keep the pad on, in case that's a problem. I had to push the cheek rest up a little to install the deflector, but there's no interference after install.
I placed the taclight so I can rotate my thumb to activate it while the rest of my hand is virtually stationary and pressing on the VFG. I want to try shooting with my thumb that way to see what happens.
I have MCARBO's choke adapter and a Briley cylinder and IC choke, but haven't installed them. I like the idea of moving the business end further from my hand and playing with chokes is a bonus. That said, the gun is 8.8 or 9 pounds unloaded now. That's a chunk to me, but the choke adapter is a lightweight addition. Anyhoo, between my brain, choke adapter, Kriss handstop and VFG, I should be able to keep my hand behind the muzzle.