I bought a universal curtain type for my FL70 in a Pilot. It works well for me. I have seen those screens that are circular and spring out in Wal-Mart and thought about using two of those.
Get the really BIG silver folding screens. They are at RV dealers like Camping World. Then cut to fit the M2. We also cut panels to fit the side windows. Velcro holds them in place.
we have the same thing lanier, those curtains absorb the heat very well...and when they're hot...they are much easier to fold up. we have the m2 also and the curtains store nicely behind the seats