My question is, if "top 10" is selected and less than 10 play, is the prize fund recalculated or if for example only 6 play, the 7-10 monies are forfeited?
Unfortunately, the rules and FAQ don't tell anything about it.
From a former FAQ version, I saved the "70 payout" rules, and they delt with an incomplete field with the general statement
"The entire tournament purse will be paid out regardless of how many entrants there are in the tournament."
and a detailled description how they would proceed.
In their texts about CC tournament payouts, there was no such text. Thus, I'm guessing that the unclaimed monies in CC tourneys might always have been forfeited.