We are running weekly tournaments with a Round Robin pool stage then Top16 in a Double Elimination Tournament.
We want to be able to say that we should always have 8 groups with the Top2 from each advancing, and players should be balanced across the groups.

Currently we would need to round up the number of players to the nearest "breakpoint" (32/40/48/56/64) with "dummy players", select the correct group size for each of those breakpoints (4/5/6/7/8), seed the dummy players into each group and DQ them after starting the Group stage.