In order to better experience High G Blackout(positive g) and Redout(negative g), you should assign the G Limiter mapping to something. Joystick trigger is perfect for this, in msfs.
Engaging the G Limiter overrides the FCC(Flight Control Computers) in the FCS(Flight Control System). The FCS/FCC are very complicated and have many more functions, restrictions and effects.
But the G Limiter should do two things:
Enable higher g and allow a faster roll rate (but this doesn’t seem to be modeled yet).
For simplicity in explaining:
7.5g is the FCS normal limit. This will change with aircraft speed, weight and other items.
Engaging the g limiter allows up to an additional 33% if the FCS safeties are met.
In other words, you can and will experience different max g forces at any given moment in flight, with or without the limiter engaged.
Without using the limiter and while you pull max sustained high g’s, watch the g indicator on the hud. Notice how it will go to about 7.5(can go beyond momentarily) but will constantly change. You might notice strange behavior also, your turn may not be smooth. This is the FCS controlling the aircraft.
The other settings that will effect your ability to have blackout/redout are in the assistance settings.
Selecting G Suit off and Civilian Pilot will quicken the onset and happen at a lower g for black/red out.
Also maybe better settings for xbox users, if g limiter is awkward to map and you want easy black/red out.
Note: Other military jets may not use the assistance settings or perhaps incorporate their own settings?
Still work to be done on the default Super Hornet, but it’s come a long way.
Hopefully it keeps getting the attention it deserves!
Max g is 9.8g for me, so far.
Overstress does not appear to be modeled yet, but that may need above 9.9g.
Hard to break it when the aircraft is trying to protect itself from yahoos 
Blackout just before full blackout. Sustained 9g, g limiter engaged. Fuel about 6.5, G Suit On, Jet Pilot. Default F18E.
(though it was silly to post a completely black picture 
)
Redout started about -2.5g with G effects set as shown above picture. Default F18E.
Probably should add:
To recover from a black/red out, relax the stick to neutral, lower throttle if desired/required and wait it out. Hopefully you still have some space between the mud and you…
-Recovery time may be a little too quick. Perhaps intentionally.
I could imagine some thinking they broke msfs or some kind of bug, if it lasted more than few seconds.
Also, if your pc user.
Consider using @Raynen 's Performance and Fuel Mod Recommend it !