Then you had better know were the pressure points are for that limb in the pelvic area are.
You need at apply the TQ at least 2 inches above the wound, with an amputation I would try to go even higher. From the 911 call it sounds like the Left leg could have had a TQ placed (amputated at the knee), but the Right leg may have been to high of an amputation to effectively place a TQ.
This is what Hemostatic Agents were developed/improved for. Cpl. Jamie Smith who died in the 1993 Battle of Mogadishu (Blackhawk Down) died from a high femoral artery injury, too high for a tourniquet. Currently Combat Gauze is the best Hemostatic Agent available on the market and the only one the military uses. It is not exothermic, it is easy to debris the wound, and it saves lives.
Just as important is learning proper wound packing techniques. If you have a GSW to the thigh and the femoral artery is severed, direct pressure alone will probably not do the trick, there is just too much muscle mass for the average person to compress and stop/control a severe hemorrhage. If you have good wound packing techniques you can stop a femoral bleed with standard gauze.
As a far as TQ time, if you put one on, you leave it one until they have arrived at the hospital. There are a few caveats to this but for 99.9% of the time it stays on until they get to the hospital and the docs can prepare for and treat the acidosis. Acidosis can be treated (you have time to treat this), severe blood loss cannot (you do not have time to treat this).