Idk if that sig brace has any provisions for mounting a sling but I have a similar setup with an sb brace. I was able to find a qd socket with a 1/4x20 threaded bolt attached on Amazon. On the bottom portion of the kns adapter I drilled and tapped a 1/4x20 hole(leaving room for the brace to fold/function). After cutting the qd bolt flush to the inside portion of the adapter(just low of centered on the flange) I torqued the socket down to 25 ft lbs with a drop of red loctite.
It's currently 7 and 1/32" - I'm going to make the next one 7 1/16" and sand it until fits, and this one I'm going to sand down until I can fit a 1/8" faucet washer (purchased in bulk for unrelated purposes) in there and I'll see which I like better.
Mil-spec lower
Anderson sport upper
BCM mod 3
Mil-spec CMMG bolt release, mag catch and takedown/pivot pins
Mil-spec CMMG trigger with JP trigger/hammer springs
Radian Talon safety
BCM trigger guard
KNS pic adapter
FS1913A brace with paracord wrap and multi-cam black Flatline Fiber Co strap
Mil-spec CH with extended latch
CMMG bolt and dedicated barrel, 4.5”
Midwest Industries MI-CRM7 7” rail
Magpul hand stop kit
Silencerco Warlock
Primary Arms 1x MicroPrism SLX on ADM QD mount
Magpul Mbus Pros
Mad Dog 10rd mag
Arisaka 300 w/ Z68 on Arisaka mlok offset mount
One of these in between back of bolt and KNS adapter.
Pic here
Mil-spec lower Anderson sport upper BCM mod 3 Mil-spec CMMG bolt release, mag catch and takedown/pivot pins Mil-spec CMMG trigger with JP trigger/hammer springs Radian Talon safety BCM trigger guard KNS pic adapter FS1913A brace with paracord wrap and multi-cam black Flatline Fiber Co strap Mil-spec CH with extended latch CMMG bolt and dedicated barrel, 4.5” Midwest Industries MI-CRM7 7” rail IWC barrier stop Silencerco Warlock PA MD-ADS dot on PA mount One of these in between back of bolt and KNS adapter. Pic here
Some supercheap red dot I got from amazon. https://www.amazon.com/gp/product/B01HPWATOC
Does red and green reticules and hasn't broken yet... Bought it for non-gun use, actually. But it was sitting in a drawer and this needed an aiming device.