Can I ask, once the three heroes have been used and discarded and there are still turns left, do you refresh the track with another three?
Also just to confirm once all map slots are taken and there are turns left those counters are useless?
Regarding the hero track:
every time a hero is used, all heroes are moved up on the Hero track, then draw a new Hero card and place it face up
on the lowest space of the Hero track. That way, in every round there will be 3 heroes available on track (except if a god's special ability does not allow it, that is)
As for the slots/tokens:
in a 2 player game, each starts with 3 tokens (for a total of 6)
in a 3 player game, each starts with 2 tokens (for a total of 6)
in a 4 player game, each starts with 2 tokens (for a total of 8).
In our map of 8 slots, the only way for all slots to be taken is the 4th player to make his/her 2nd move, bringing the current turn to an end. So there are never useless tokens.
I hope that clarifies what you asked!