I guess I'm not following you.

I would most definetley take a quartering away shot and hit both lungs. Not a problem. If the angle it too severe though, I wouldn't.

Getting both lungs should be a 100% recovery rate. Getting only one is not. According to John Trout (who is an expert in deer recovery), a single lung hit deer is his least favorite hit to track. Success rate of recovery is low. Now, I'm talking one lung, nothing else.

IMO, aiming at a spine is not ethical. Hey, that's just my opinion. And I would never purposely aim at the spine.

Now if I was confident I could hit a heart on a straight down shot, I'd do it. My problem is having to get through all of that bone that is in my way. To tell the truth, penetration is only part of the reason. The other is arrow deflection. Have you ever seen how an arrow will deflect by just hitting a branch, stick, leaves, etc? Why would I think any other different that bone could not deflect an arrow? Now, if I get that deflection, I'm more then likey to get one lung, which I already stated that I didn't want to do.

TeeJay, what this amounts to is my opinion vs. your on the shot. I have presented my case and you have presented yours. If I absolutely had to put meat on the table, my opinion might be different. But, at this stage of the game I am here to enjoy hunting as part of the archery sport. Possibly wounding an animal is not very much fun. I wish you well, and hope everything works out for you - really.