(x/2160) * y with x being the number of hours you hold NXT and y being your NXT balance.
Therefore if you wait until the last month (720 hours) before the snapshot you will only get 720/2160 = 0.33333333 ARDR per NXT you buy.
Personally I dont think 2k sat will be happening within the snapshot period, because that whole Ardor thing put Nxt back in the focus. We have lots of new people interested and invested in Nxt/Ardor as a tech. Many of them will stay until the snapshot of July 2017.
I wonder if the developer of this project still exist? I think it will also affect the price of the coin. I was holding some NXT but not intended for trading. I just use it for transferring another coin in other exchanging sites. I was just making up my mind if I will invest i this coin for trading. Just making some research