People have used shorty pads for years, ie 48" length... (of course, nearly everyone doing so is significantly taller than 48 inches).
But the Neo is about comfort, I guess. Your head doesn't need to be on the pad. My pillow is typically my shoes, overlaid with a Platy, overlaid with a shirt of some kind. Even as a side sleeper I have plenty of pillow.
Pad fit isn't nearly as critical to have exactly right as sleeping bags or insulating layers. Go for the regular...