1.If the larger panel will EVER be shaded by overhead stuff, such as the backstay, ect,, and if splitting it to two will allow one to be out of the shade, then go that route
2. If you are going cruising to far-away places, than consider being able to bring the panels down the companionway
, with the mounts installed. It is nice to be able to bring them down below, if a bad storm (think hurricane) is forecast
. If you are sailing on weekends, and can bring them home, than this is not an issue.