RE: if you have to let one go overnight before tracking...
Unless it’s raining or very wet from a recent rain, I actually find it easy to track a bloodtrail at night. The wet blood trail usually catches the light of my flashlight. Of course, if it’s raining, it’s probably best to track the deer immediately anyways, or you may lose the bloodtrail.
I’m a “wait 30 minutes guy”, not a “wait hours and hours” guy, when it comes to tracking a shot animal in any case. I’d rather not wait until the next day. Unless I’m really hungry, I don’t like to eat meat that smells or tastes “funny”, even if it’s safe.