Here's the suggestion: Before the smithore trade auction for N, indicate how many plots are planned to be auctioned on N+1. Obviously, this will depend on availability -- if there aren't that many plots left after the land grab, there aren't that many plots left -- and whether or not an unsold plot will stop additional sells.
This is why it's a game and not a deterministic simulation. If you know what's coming, then you've solved the game. Solved games aren't fun.
Not even the computer knows how many plots it will auction next round. The point is to play the percentages and either prepare for it, or risk not having the cash and hoping no plots are auctioned.