I think you have several leaks here most likely. PCV system is almost certainly leaking with a hose like that and if that hose is that way I would suspect other hoses are also not up to the task. Also, why do you continue to seek advice and troubleshoot a problem with a vac leak like that? You know there's a leak because as it's been stated before the vac gauge should be around 20" (it's not -20, it's 20") without a leak in the system. I recently found a vacuum nipple under my throttle body that I was not aware of which wasn't hooked up and it was idling at about 18" and now it's idling at 21" vac.
Fix the vacuum leak. Then go from there if the problem persists. I haven't had much success with spraying carb cleaner. Bring it to a shop and have them hook up a smoke machine to it to verify there's no leaks.