I doubt you will need to go this far, but when I started using allen head screws, they stayed in much better than phillips head screws because if you have a good set of hexwrenches, then you can torque the screws much more firmly.
Make sure that the screw threads are clean as well. I just use a rag to clean them as well as some motor spray. Then put on a little thread lock (not a huge blob), and firmly torque the screw down.