Ook wrote:

Excellent advice everyone, thanks. I'm going to set 25-30 posts, but not all
at once. I expect it to be an ongoing project for several weeks. Any
thoughts on how many holes a 80# bag will do? Or how many bags per hole? The
bags are cheap enough, and it sounds like it might be my best bet to just do
it a bag at a time.

you get about 2/3 of an 80lb bag of crete in an 18"-24" deep hole
(about 6 - 8" diameter )

or... the math would be, 60 lbs per post

I used to run my own fence and gate company, i got this thing down to a
science

for concrete, I used to pour one gallon of water into a 5 gallon
bucket, and top off with concrete
(that's all the hole would get.. one 5 ga buckets worth is going to be
a little more than one hole needs)
then I used a shovel to chop the mix in the bucket.. it doesnt take
much to get the mix you need...
more mixing gets done on the pour and on the stabbing.

it's also good to stab the wet concrete while you are plumbing the post

I hate setting posts anymore, it's alot of shoulder work

depending on the ground you are digging in, for 35 posts, you might
think about renting an auger.
for 40-50 bux, it is sooo worth the cost! trust me. you can drill all
the holes in one day, then set them in a couple days.

our home supply shop sells 60lb bags of concrete (perfect for one
hole)... and oh so nice on a fella's back