RE: what do you set your bow at?
 

I guess it comes down to "Shoot the Highest weight you can draw comfortably"......if you CAN draw a certain weight easily then why lower your performance by shooting a lower weight just to shoot a lower weight.
I know in a perfect world you may not need the extra 10 or 20#'s of draw weight, but shoulder blades, spines, and ribs aren't really a perfect world.......
I shoot 70#'s on all my hunting bows because that's what I feel comfortable with......bonus that I'm getting some extra usable energy.
If you can draw a certain weight in odd positions, cold, under pressure and hold on target for a minute or 2 if you have to, then by all means that's the weight to be shooting.
Don't handicap yourself because you "Probably don't REALLY need it".

RE: what do you set your bow at?
 

Lightweight bows can handle whitetails quite effectively. But, if you can handle more draw weight without a loss in accuracy, you have the primary advantage of being able to shoot a heavier arrow for more penetration and the secondary advantage of getting a flatter trajectory. My own bow this season draws 65# @ my 25" draw. I have two sets of arrows...620 grain primary hunting arrows and 800 grain engine block tamers that I plan to use when hunting in close quarters. I have other bows I may switch hit with that draw 70# and 60#...depending on how cold it gets. :^)