I went off of the 2oz spec and converted to newtons: 0.57N. Then used one of my classroom Vernier force sensors. From an absolute force frame of reference, that’s pretty much nothing and feels like a stiff breeze will push the trap open.
Measuring it on field seems loosely goosey to be honest.
I agree that field set up people will likely just push it and say “Seems good.”
Are you sure? When the flap is pushed mostly open into a vertical position, the top of the flap hits the back of the support, stopping the top from moving further. But the bottom can be pushed a little farther back until it hits the stop, so at this point you’re flexing the flap and getting a spring-like restoring force.
I can all but guarantee you this spring behavior of the poly carb is greater than 2 oz and not the area FIRST was intending to measure against. A glance at the field tour video makes it pretty obvious there is not need to force the flap on the trap much at all.