High shoulder is your best bet if you can't afford to have them run. Not a guarantee, but it gives you better odds. I usually take lung shots though and like you my deer always run for a ways before they pile up.

My honest opinion is a heart lung shot will kill them faster, but a shoulder shot will usually drop them. Remember just because it falls doesn't mean it's dead, just immobile. End result is usually the same though. Just like shooting a person in the hip. They will hit the ground for sure, but they won't really die until they bleed to death.

Paul