Deb,
As for holding the Lexan etc storms in place? NO holes with holding screws going thru them as it leads to cracks propagating from the mounting hole. The only hole may be for the lower RV tip out window crank out shaft to pass thru so the tip out window cab opened without taking the storm off. Will explain later. All of our storms I make/made are clamped on by using some of the existing window frame mounting screws. Depending on window size, I take out 2-3 on top and bottom, 1-2 on each side, place the appropriate sized fender washer on 2 of the screws so it will clamp on a sizable area of the Lexan when tightened. Put 2 of these screws back in on the bottom of the RV frame and leave plenty loose. It givs a loading shelf to set the storm on while putting in the other screws having either more fender washers or plastic turn screen door clamps, or plastic mirror holding clamps etc. What ever is best for the situation. Pre-spray paint the washers etc black if you don't want to see them and they leterally disappear. So many different window type so you have to use what works on any particular window. One person can easily and very quickly put a storm in or take it out. 1-2 minutes each once you get the hang of it. Even quicker if using turn clamps.
I go a step further as I put a small stainless steel hinged little window in the storm about 6" X 12" in size overlapping the storm window cutout hole in the kitchen window storm near the range. It stays toghtly closed thanks to a Velcro strap and instantly held open when wanted thanks to that same Velcro strap. Why the window in the storm? We seal all our range hood vents in winter and need a way to exhaust cooking heat or moisture effectively like anyone else. Open the little window and crank out the tip out window a little and open a roof vent a little when doing serious cooking and out goes the moisture etc and so fast. When done close them up and you are in true sealed/weatherized mode again with all storms in place. Might take all of 10 seconds to go from true seal to true vent! Remember that heated air always rises naturally and takes with it the humidity and cooking odors and fast.
I've written many times about this feature and many forum members have contacted me about doing it and how. I selectively email pics to those I feel I want to help as there are several on forums I choose not to communicate with period let alone send emails and I don't have to explain why! They know who they are!