29.92"Hg is a perfect vacuum and pretty close to impossible to get without NASA or a university as you have to approach absolute zero and radiation shielding. 29 is about 96% vacuum and 27 is about 90% and 24 about 80%.
A perfect vacuum is unattainable with even the best gear ANYWHERE, due to OUTGASSING. This is when the vaccum is so powerful it literally pulls oxygen from out of the materials used to make the chamber. Think of it this way, one cubic cm of the air we breath has over 30 quintillion molecules. The best scientists have been able to do is what is know as a super high vacuum, which in one cubic cm their are only 100 molecules. Below 100 molecules per cubis cm, outgassing occurs and it stays at 100. To put that in perspective, the space between planets only has 10 molecules per cubic cm, interstellar space has 1 per cubic cm, and intergalactic space has 1 molecule per cubic meter! Damn! And the vacuum cleaners that we use to clean our homes with, at sea level only have the air thinness of Denver in the operational part (the vacuum chamber).
Back to OUTGASSING, that is what you are trying to achieve with the hash, remove as much gass (in this case butane) as possible. So in theory the better the vacuum rate the better the extraction of gasses, simple.
Long story short you cannot have a perfect vacuum, even in the deepest reaches of space- its not a perfect vacuum. Like this if you have any more questions about vacuums!
