i used 303 instead of raggtopp, much cheaper and can be found at murrays or autozone. it did wonders on my top.
i love watching ALL the water just fly right off the top when i was the car.
one month without storage should be fine, but if you are really picky a cover is fine.
my buddy's license is suspended for a year, been 11 months now, and his car still sits w no cover haha, it still looks same.