The Nightcap can take 3 or 4 hole shrouds. Not sure there's any value to the 4 hole there, as it goes through a plate of sorts inside the nightcap, so the 3 hole seems rigid enough.
Do certainly get something countoured. The old school Norotos plates are no good here. I say, spend the extra for something as light as you can afford also. The Nightcap is small and light, so we're to the every-ounce-counts territory I say.
There's not much else on the nightcap itself, so make sure you have all accessories you need on the shroud. If you use the Wilcox lanyard (or may in the future) make sure you have that attachment hole. I do lots of home-brew silly ass stuff (e.g. my own lanyards), so got a skeletonized one, so I can loosen a tidge and wrap cords etc through the outside bits.