Scheduling of signals

We are doing a data load overnight and I have 7 signals that need to run after the data has been loaded. Some of the signals take longer than others and because the length of time they take to run is dependant on the amount of data pushed, timing may be variable. My understanding is that signals are processed by gearman slow and that they will be processed sequentially.

If because a large amount of data is loaded one night and a signal takes longer than expected, if the signal hasn’t finished before the next signal is scheduled to start, will the next signal just queue and run after the previous one has finished. Ie signals will complete in the order they are scheduled even if they start later than planned.

Also, once a signal is finished is it possible to trigger an email to tell people that it is finished?