I can't speak too much on Shirogane. I'm not that impressed with the plots there. Not sure how desirable these plots are, but they're the ones I like.

Mist - 29/59 medium and 14/44 medium - the latter is what I chose for my FC house and I love the view
Lav Beds - 29/59 small on the island and 28/58 large on the island next to it
Goblet - 11/41 - medium - this is my personal house and I love it for how it's surrounded by cliffs on all sides

I don't have too much of an opinion on other larges