The high pressure event is when the bullet is still very near to the chamber, so what you will be getting in terms of high pressure will have something to do with the peak pressure and more with how your gas action treats the case upon extraction.
To a degree, higher pressure will also cause higher extraction forces if the pressure is high at the port, but those are secondary effects compared to the pressure at the chamber end when the bullet is seeing factors more pressure.
That said, it is worth a look but don't spend too much time with the port closed if you intend to run the gun normally later on.