and so you would stick with momument and no soothsayer?
I don't think Soothsayer is very good with Hunting Party. Once your opponent has one Curse in hand, his HPs will skip over the rest. The extra unique card does hurt him significantly, but not more than Soothsayer hurts you. If you go for Soothsayer, you're mostly hoping that you can curse him enough that sometimes he has turns without Hunting Parties at all, but if you get Soothsayer after the Hunting Parties are gone, there won't be enough time to make a difference, and if you get it over a Hunting Party earlier, then you're letting your opponent buy more Hunting Parties which defeats the purpose (plus Soothsayer itself doesn't help you buy another Hunting Party while it's in your hand, which might turn out to be annoying). The Golds you gain aren't that important either since you should generally be drawing each unique card in your deck every turn anyway and normally that's enough for a Province, and you're also giving your opponent a +card every time you play it.
Compared to Monument, Monument (probably more than) makes up for the VP you lose from the Curses, gives you $2 and doesn't compete with Hunting Party at the $5 price point. I would stick with Monument and no Soothsayer.