I know this one will have many answers, depending on what company your dealing with.
As an example, I had several jobs in a cluster and it was only worth doing them, if I could get all of them. The MSC was the type where you apply and wait.
I called the scheduler and asked for all or none, and 30 seconds later, they were all assigned to me.
This company answers the phone and even has the extension of the scheduler of the project in the job information area. Some companies don't have it so nice.....
I have applied with other companies days in advance and got no reply, and didn't want to be blindsided at the last minute and removed my application to the job, instead of being assigned at the last minute or even worse, during the actual shop window!
How do the veteran shoppers handle companies that leave you hanging and your trying to make a route?
When I have to make a choice, I will withdraw my application to a shop, so as to not get blind sighted with it on the due date if I can't reach a scheduler.