I spun up a proper alloy plug with a step so the hose clamp doesn't pop off, the hose runs to a gauge and trigger setup. I can tell you, at 40psi there is not much chance of sealing all the leaks, unless you glued them perhaps. Most would say it's overkill to pump that much in, but I run nearly 3 bar at gearchange.
If you are worried about the AFM, take it out of the equation, why would you run it in the system anyway? Just remove the afm/airbox, stick the bung in, and pressurize.