You need with a one way valve in it and lots buy a hd pump, with a bike pump from a big box as u take it off you will loose pressure. If you over pump it you have to remove the pump and push the center of the valve to release. Fronts are 7psi max. Also a way to pump up your tires.
same is going to go for those straps, get the contour of the straps so that they sit reasonably flat on the trunk, move the marked tape to them. you will be fine.
Never use rain-x or product intended for glass, I use one made for motorcycle windshield. You have to clean first and I use windex wipes, then apply with a microfiber and polish with another microfiber.
Never got a template, put some frog tape on it, mount it centered nearer the front , drill one hole at a time. mine has stainless straps top and bottom and some rubber washers ontop.
I put some foam grip covers on and it makes it a lot easier to grab, use or try to use the cruise on the open road. Try getting in the habit of using the kill switch to stop and turning it on when u want to start ir. that will build mucle memory.