[3gm]

When asked to substitute, it would be helpful to know the potential time commitment (#boards remaining x time/board). That way you don't accept a substitute position that you can't complete.

[0 carbon]

And, ideally, something like:
"Scheduled finish 1824"
based on boards remaining for the substituted player & time/board.

This avoids the sub having to do calculations.

Also, no replacements should be made when BBO knows the sub is scheduled to start a tourney before the scheduled finish!
(Plus 5 minutes if unclocked)