I'm not Bob but I'd like to give my .02. Actually you answered it yourself...........
why we would worry about "limitations" or whether or not we could get a sure vitals shot on a deer
most likley mortally wounded and in need of being dispatched, quickly
Seems like the best way to dispatch it quickly is to do everything in your power to hit the vitals rather than hit the deer.
50-70 yds? Sure. Every time.Shot facing straight away? Most definitely. Quartering to? Yep. See a pattern?
How many arrows do you carry?[8D]