My thoughts on how a time bank could function:
Let's say: you have 3 minutes for placements and 1 minute for regular turns (default times)
On top of that, you have a 5-minute time bank.
If you need more time than the default times, you press the time bank and the time bank clock starts running down. When you've made a decision and ended the turn, the time bank stops as well.
Let's say you took 2 min and 20 seconds for a regular turn (by activating the time bank). So, you used 1.20 of the time bank's clock.
Now, you still 3 min and 40 seconds left in the time bank to access on another turn.
I believe a time bank can create very interesting game modes. For example:
- 1 minute for every turn + a 10-minute time bank (time becomes an extra resource)
- the perfect mode for competitive play: slow mode + a 5-minute time bank (obviously the numbers need refinement, because I haven't played with a time bank before and I'm making guess what would be perfect)