Homebrew PCBs

Using, in this example, a 2 sided positive acting pre-sensitized board. I have well constructed frame to hold the pcb and film in place while exposing to light.  
How would you go about getting both sides ready for etching?  So far I see side 1 being exposed.  After that comes ( and this is where I am asking about the process order) developing of side 1 circuit, drilling registration holes, exposing side 2, developing side 2.  Last step of course is etching.  
I am concerned about the handling of the board during these processes.  The frame is tight, and I don't want to be scratching or scraping away any of the resist while messing around.

As an example, do I drill registration holes prior to any exposure at all, side 1 or side 2?  Do I develop both sides at same time? 
Or, do I do side 1 exposure, develop, drill registration, and then move to side 2?  This makes me wonder, can I develop side 1 and later do side 2?  Will that double dipping mess up the first developing?

Regarding the registration.  How will I keep the film from sliding around and become off target while placing in the exposure frame.  Can't use pins, unless I cut them short enough to hold the film to the board, but not extend pass the board.  Do I glue the film to the board?  Tension on the pcb/film is supplied by the frame via sliding the back panel of the frame across the back side of the pcb.  This creates a shear that will move things around.