I'm sure 20 people will provide 20 different answers to this one, but I personally think that 10 yds is perfectly acceptable for a boiler room shot. It all depends on the animal, the alignment of the stars, the tides, and all manner of uknown variables that I don't pretend to understand.
Obviously a .30-06 provides plenty of oomph to cleanly take a whitetail and the lack of an exit means the animal took all of the available energy, so I don't necessarily think that a change in bullets is going to guarantee anything on a heart and lung shot... Now that being said, a shot with a stout bullet through both shoulders might up your chances, but still not a guarantee of a straight drop. If drop on the spot results are what you want, I would recommend a head shot or at least a solid neck shot. My own experience would dictate that you have roughly a 50/50 chance of putting a deer straight down with a good broadside lung shot. Sooo...if you shot 10 deer and the first 5 dropped like stones, and the last 5 ran ten yds, would you feel like you needed to change bullets?? Personally I'd feel pretty satisfied.
This wasn't exactly what you were asking for, so forgive me, I felt a slightly different perspective might be helpful. By the way, congratulations on the deer. :grin: