Well, PicrosST -full edition- is more a 2 players cooperative game. But it has also a score record management.
The thing is : it's only available when the first 99 puzzles have been solved
I think the ac2008 edition (which has been made especially to "sort" people during a tournament) is the best edition to play for a offline tournament. Furthermore, the score will be written on a (easily) encrypted file.
Last, but not least, the ac2008 edition is much more stable than the full edition (which has a new release today and will have more)
So I'd recomand "full edition" to practice and to play with a friend, "ac2008 edition" for the tournament.
If there is a lot of players who will play this tournament (I won't, too much practice...
) I'll give here the algorithm used to calculate the score on the "ac2008 edition"...
Waiting for your answers,
PS: I made a link on the rss feed of picrossST for this tournament ( http://picrossst.free.fr/news.rss