in reading the comments i found where he posted his supplier which is in canada
Home - Omni Structures International
if i try something like this i may end up using greenhouse poly (actually vinyl is what i have a roll of)
and a wood frame with the layers of poly physically held separated by the wood frame
where i want to build i may have to do 3 or 4 layers(in combination with other methods) but as he says in the video the bigger the zone difference the more protection required