In order to keep this going I am summarizing the current situation:
First, it seems that the majority of players do not want any overtime at all, as you can see in
this thread! If you have not voted yet whether overtime should be used or not, you should do so asap.
As there is really not much thrown in by the community about the map selection process, I'd like to pick up k0jak's idea. However, there are still things being unclear.
What is already decided:
During the group stage, for each round there will be defined maps (all three maps will be defined). This helps the maps popularity to grow and to explore the whole map pool, it also forces the players to prove an allround knowledge of the pool.
In the bracket elimination stage it is already decided that the players can choose their own map. When it comes to a 3rd map players should agree on a map. If they can not agree to one map they will have to start an elimination process:
First, the player who starts eliminating maps has to be defined (not sure yet how to do that). Then this player has to build a list of all maps of the mappool, however, without the 2 maps that were already played. Then the player who is supposed to start removes one map from this list. Then the other player removes a map from the list. The players take turns removing maps until only one map in the list is left, this map is the deciding map.
What is not yet decided:
a) in what way the three defined maps (for the group stage) are selected. Either manually, or randomly? If randomly, how to do that then? This also depends on the number of rounds. The goal is to actually have every map of the pool to be used at least once. So I suggest to distribute all maps among all the rounds first (and randomly) and then manually decide on the distribution of what is left.
b) How to determine the player who starts eliminating maps: could be done by having a look at the total individual scores of both players (adding them together and see who's got more).
Ideas are always welcome.