Flatout, this is one of the tougher shot selections and one that usually should be avoided.
You did not say if you would be in a tree or on the ground, out west we are usually on the ground and it is a different shot angle than from a tree.
Your arrow weight should be suffiant, you did not say the weight of your bow.
Most experienced bow hunters will avoid this shot, my self included, however, there are times that I have taken this shot, but every thing must be perfect for me to take it.
This buck was shot on the ground @ 12 yards 55lb Habu with a supper skinny shaft and a grizzly 160 arrow weight was 530grains.
This buck was also shot on the ground @ 8 yards 60lb Abbot with a snuffer, a 525 grain arrow, you see the broken shaft in its chest.
This buck was also shot on the ground at 12 yards with a 60lb Widow, snuffer and 525 grain arrow, head on.