That is wonderful you want/have professional built tunnels. Now wait you said you would like and then you said you have. I am confused. Which is it? Owning these high value crops you have I would hope you would know the difference. If they are professional steel tubing why are you even concerned about the pvc or for that matter the cattle panels? I knew by the questions you are asking there is more to the story. I hope we can all get to the point where we can want/have professional steel model hoop houses that are bent to the correct shape with high value crops in them.
This unit is a DIY unit not a professional. This is to help those on their homestead when trying to be self sufficient and cant afford professional equipment like others to be able to build the equivalent, similar to or close enough of a processional model themselves. When being self sufficient I think most believe like we do - function over looks. This functions wonderfully and looks nice. On a lot of homesteads we probably have a few cattle panels laying around along with some boards and can probably build this for the price of just the greenhouse plastic, but we are not going into that now.
You are 100% correct I have no experience with snow, but if you go back and read the comment I made it reads we have reports that the snow just rolls off.