I think your doing the right thing trying to eliminate a problem before it becomes a problem with selecting the exact shot you want to make.
It sounds like your shot isn't going to be too far so I'd opt with drilling the heart right outand would go forthe high shoulder/spine shot 2nd.

But now address the other foreseen problem and that is the neighbors and the possible trespassing issue.

I would make contact with the neighbors ASAP to clarify your intentions. Let them know you are going to be hunting over there and find out if anyone is expected over there on their property, youdon't want to shoot at/towards anyone and youdon't want stuff flying in your direction either.

Maybe nobody is supposed tohunt there and the signs are up because of trespassers in the past. Let them know you'll report any trespassers to them if they would like. Ask if you can retreive your downed game from their property right off or if they would like you to check in with them first. Maybe as simple as a phone call. But IMO communication is the key and can sometimes open doors you never even knew were there.

Maybe the neighbors aren't "the hunting type" but enjoy venison. If you should retreive from their property (or even not) turning them on to afresh, roast wrapped in bacon may pay "dividends" later if you know what I mean. You might even go over and introduce yourself as I mentioned earlier and they may think they need a few deer taken off their land (thin the herd).

Good luck and be safe.