Update:
I'm not sure this black plastic, shrunk with a heat gun is going to be a good medium-term solution when there are large temperature variations.
The weather has been pretty cold since I initially built the cover and the plastic remained tight and looked pretty good.
Last week we got some more warmth and the heat from the sun the plastic started to expand and wrinkle. I'm now pretty concerned about what it will look like after things really heat up.
I wonder if it was shrunk using the heat guns used for boats if it would have worked better as it would be a more uniform shrink.
However, this is not likely to be a great method for any type of long-term use.
I think I'm headed back to the drawing room to figure out version 2.0. I'm also considering doing some testing to determine how much difference there is between a snugtop style topper, a tonneau, and this topper for this particular truck. I may end up going a different route if there is not a significant difference.
On a positive note - I did just get my second highest tank ever at 19.04 MPG for a whole tank. I'm definitely excited to see what happens when things really warm up