Solar covers don't last long. Two years is pretty much on the low side but four would be alot. I haven't seen reel designs for Intex type pools and I haven't seen AG reels that I like at all but Watermom has ordered something that intruiges me, see the middle of page two of this thread where she mentions solar roller. I will order one if she finds it works anywhere near as well as it looks like it will. As far as what kind of cover to get - hard to say, I've yet to see any performance information. Color, I like blue cause I like to see my pool blue. Get one cut to shape if you can. 12 mil may not last as long but may be eaiser to handle than 16mil - 24ft is pretty big. Watermom cut hers into quarter pie slices to facilitate handling.

As far as roof mounted solar panels, I believe they are made for permanent mounting. Minnesota (where I grew up) may be an outlier. Check with the manufacturer. Be sure the plumbing to the panels and the panels will all drain down. Did you plumb it yourself? Does this roof get ice dams without the panels? Is the roof dark or light in color?