In an ideal world, we'd all train and qualify with back-up and off-duty guns from the holsters we carry our OD/BU guns in. In the real world, firearms instructors only have so much time. If an officer is smart enough that he or she carries a secondary handgun, I'd hope he or she would be smart enough to practice their presentation and holstering on their own. That's not a perfect solution, but it is a solution. We also were flexible with time/reloading mandates on off-duty/back-up qualifications because we were realistic. It would be stupid to prohibit someone from carrying a secondary weapon because the magazine capacity wasn't the same as the duty weapon.