Ok, I'll accept that. I thought I remembered hearing that before running the course, shooters are allowed to do a walk through. Also, most competitive shooters I've read about develop their own loads to maintain accuracy with less recoil.
Yes, you are allowed time to walk through and develop a plan. In my experience, about 60% (down from 100% when I started ) of the time, that plan goes to **** as soon as the buzzer sounds (though this is likely why no one watches videos of me shooting). As far as load development, you HAVE to make power factor. There's no cheating with mouse-fart loads (which likely wouldn't cycle the Open guns anyway). Your ammo will tested at major matches.