Just a bit of thread drift.
If you are considering locks on BOTH doors, realize that if the door is locked you will be unable to open it from the inside.
This maybe problematic if for some reason you are flying with the pax door locked, have some sort of problem, and need to vacate through that door. If it is locked from the outside, it will not open from the inside and there is no way to unlock it from the inside.
Aerosport has blank trim covers for the outside if you decide not to put a lock there.
The question then, is how to lock the pax door when the airplane will remain unattended or RON. It is a simple matter to use a readily available nylon loop around the handle and seat rail. Locks the door but is unlockable from inside...
Definitely a personal preference but I though I would put it out there...