Ben,
Not to make this even more complicated for you, but there are MANY considerations in a cover!
Is it just for rain? Do you get snow and ice? Do you get HAIL, the real airplane killer?
Do you live in a COLD place where you might want to cover your engine and pre-heat?
Does your entire plane need covering from the prolonged exposure to the Sun and environment?
I have been through MANY cover considerations and have tried various combinations and permutations of covers...
I finally went with FULL COVERS for the elements and to ameliorate the threat of HAIL to my plane...so far, so good.