I looked into this a bit because I didn't want to drill holes in my tub. I wanted to use the clamps, but couldn't find a place who sold them locally at a reasonable price. In the end I found a place in the states (on eBay) who sent them with the topper tape.
I don't know if you already have a canopy, but mine came from a mate (I.e. 2nd hand) and two of the existing bolt holes lined up with the bolt holes from the sports bar. In the end I used two if the clamps and have two left over.
So you may get lucky if you're taking off something like a sports bar and be bale to bolt the canopy straight up.