I purchased one of these for this project:
72", 17 Lb. Digging Bar
Also went through two of these (I broke a brand new one in two, son did the same):
Shop Kobalt 14-3/8-in Post Hole Digger at Lowes.com
I fortunately have a 6' 2" teenage son who is very fit, I have quite a bit of "umph" compared to him due to my......uhem....size.
Each hole took 30 to 45 minutes with he and I switching off, plenty of rocks at the 2 foot mark.