Unfortunately I don't have any covered or dry area to park , both bikes are in my front garden and I will be wintering 1 at least
although I've never seen one of the vac bags I sort of assumed that as you remove the air from the bag with a vacuum cleaner that it would be a total vacuum , the same company manufacture the ones for clothes , bedding etc as well and they are a complete vacuum like a second skin layer The website isn't very informative with pictures but it does say it protects against rust , corrosion etc. it says to drain fuel/oil but to protect the fuel system from gumming and oil becomes acidic and corrosive to internal parts,also to remove the battery however it needs a drisorb bag to trap moisture but that only needs changing once a year.
I might take a punt on it