MGSV FOB Infiltration - Daylight nuke theft against S++ snipers in stealth

Daylight (6:00AM) Infiltration against S++-S ranked Long-range (sniper) Security Guards
Stealth infiltration example against a defender and non-lethal guards:    • MGSV FOB Infiltration - Daylight nuke thef...  

Metal Gear Solid V - The Phantom Pain
FOB Online, Steam


Loadout (important pieces):
S-1000 Air-S (Rank 7) - Customized with silencer
AM MRS-71 Rifle (Rank 7)
Stun Arm (Rank 4)
Sleep Grenade
Stun Grenade
Magazine
Noctocyanin

This method can work against any FOB defense. S++ snipers are the most difficult to sneak past without being detected, but it's possible. In this video, I was unable to achieve the perfect stealth bonus or the no reflex bonus as the visual range of alerted S-ranked snipers is higher than that of short- or mid-ranged guards.

Tips:

Roll. Notice I am looking in the direction I am rolling most of the time. You can roll in the direction you're looking by holding "W" on the keyboard or pushing forward on the control stick. Using the binoculars/ADS can quickly change your direction.
Once you destroy anything, extract a guard, or put the security team on alert, a defender can wormhole in to defend against you. If you pay attention, notice that at around 7:12 the online connection icon triggers in the top right hand corner of the screen. That was either when the UAV crashed or the security call went through, not sure which happened first. It does take around 30 seconds for a defender to respond, choose loadout, and load, so there's always a bit of time before you're in trouble.
One benefit of infiltrating against higher ranked guards is that they actually are more easily distracted by magazines. E-ranked guards look over for a few seconds and then go back to whatever they were doing. S-ranked call their buddies and run over, look around, and then go back to whatever they were doing.
Cameras can notice you at about 20-25m, and unless you move out of their visual range, you will be spotted. UAV cameras work differently, if you remain stationary and prone, they will lose sight of you and continue on their path. In both cases, it takes about 3-5 seconds for them to notice you if you're rolling away, so if you can move out of view, you'll be fine.
Avoid the platforms where two snipers hang out if you're infiltrating against snipers. That leaves only one side across which to cross a platform, but on the first platform, this means you only have to deal with one or two guards at the most.
At around the 7:20 mark, I take a couple of shots at the corner of the power generator to disable it and remove the threat of cameras or the anti-theft devices.
The gas from sleep grenades obscure vision in the same manner as the smokescreen from smoke grenades, but with the added benefit of tranquilizing any guard within its effective range. At around the 8:42 mark, notice that the guard spots me through the gas. He has nightvision, which removes that benefit of the sleep grenade.
Also around the 8:43 mark, notice that I have almost a second after reflex ends to neutralize the guard before an alert is sounded. You don't get that time when a camera spots you, the alert is sounded immediately after reflex ends.
Anytime you fire a silenced shot that hits something, guards in the vicinity of the bullet impact get a general idea of your location. Any sound you make does the same thing, like extracting a guard.
Any distraction directs the attention of guards elsewhere - note my usage of the sleep and stun grenades as I moved up the command platform. If I did not do so, there is a chance that the snipers on the previous platform would see me.
Not 100% on this last one, but there is almost always a weather effect that occurs when I infiltrate at 0600. Rain, mist, clouds, these are all beneficial as the lights won't be on during the day to decrease their advantage.