Nice job putting 2 car canopies together. That is one LONG MH! :C
That would be a less expensive way to go for the op and would be easier for the owner of the storage lot to approve it.
I used one of those tarp type canopies that are really only to be used temporarily and I left it up and out in the elements and it lasted 2 years! then all I did was buy another top.
The one with 3 poles is around 200 bucks and they are always on sale at Harbor Freight. so for two it would be $400.00 plus some added effort to secure it to the ground.
The best one I saw was a fellow RV'ers drove 2x4's into the ground and screwed the legs to the 2x4. Which in doing that you can also raise the height any length you want.