Well, I failed on the picture taking front because we had too much fun shooting to remember to take any. Yesterday went out with some guys from work and brought out, among other things, the T81 LMG. We were messing around with plates at 100 yards, ~500 yards, and one at ~850 yards. Couldn't figure out what the manufacturer was using as reference when marking the sight adjustments as when we switched from the 100 to 500 yard plate and I dialed the wheel to the 5, we were hitting like 10 feet high. Ended up dialing back down to the 1 and were correct for elevation. Then for the 850, it seemed keeping the sight on 1 and just using the top notch on the sight worked well enough. Given the wind of shooting across a small valley, the limits of our own skill, and the obvious limits of x39 bulk surplus ammo, we were making mainly just a bunch of noise and few impacts lol
Our 500 yard plate was about 8"x14" and we were dancing all around it (if it had been a 14x14 we would have hit it LOTS) with hits about every 10th shot. Our 850 yard was about a 18"x18" and we stirred up a lot of dust around it, but only hit it twice for all the rounds we chucked. As expected, of the 150 rounds we ran through the gun, zero malfunctions
Brandon Herrera described the sites like this in his recent video, https://youtu.be/1Gz-vUTc3Cw?feature=shared, on the L M

Brandon Herrera on YouTube said:...the rear sight here actually has a rotating knob that adjusts the site as necessary corresponding to a near and far sight so whether you're using the bottom or top notch is where you'll be hitting at one of the two distances ...
A now deleted Reddit member pointed out GNutzGuy on YouTube had provided a more detailed explanation in one of his videos,https://youtu.be/gllufPRtsQc?feature=shared&t=725 , at time index 12:20:
GNutzGuy on YouTube said:![]()
... you're using the bottom cut okay now here just to make it easier for you this is your rear sight if you're using one three four five hundred meters your front post which is red would be in line with the bottom cut okay if you're using six seven hundred meters your front post is now moved up to the top of the bar which is now cut