Both the cockpit cover and the full tarp are secure and tight enough for towing. The elastic cargo net minimizes the tarp "slapping" and I also put a blanket over the car to keep the tarp off the paint. As for the corners, the tarp's tight enough that it doesn't chafe. But I may still put some foam over the corners. I'd tow with it all the time if it wasn't 30 minutes of work to put on. (I'm 1/4 of the way home in 30 minutes).that looks awesome! the only thing i'd kind of be worried about is the front corners of the trailer look like they might poke through the tarp if they are stressed. Do you tow it with the tarp on or is that just for when it's parked?
One other thing about open trailers (if this wasn't said above), have a full deck to avoid spray and crap coming up from below. Add your own plywood if you have to.