You should probably stick to your DZ`s policy Bergen. Unless you are using some strange student canopies spending thousands of feet to open. In that case you should get new student canopies.
There is a ten second window from 2000 feet to 1000 feet in freefall, giving anyone heeps of time to jump, pull and cutaway if needed.
When it comes to staticlines I would just get them to bail out as fast as possible, but we use the method mentioned by riggerrob where all students are hooked up prior to takeoff. It is an emergency and time is of essence. An alternative(if student is hooked up) is to pull the students cutawayhandle prior to exit which would give them an RSL deployed reserve and no danger of two canopies out. But do not think i would recommend it. Better to have two canopies then no canopy.