well i stayed around 7 feet deep, i would fill about 5 5 gallon buckets with water for ever 5 gallon bucket of dirt. i just could not keep up with the water coming in the hole. so i went and got a 10 foot piece of 6inch PVC and drilled holes in it and put it in the hole. My first choice would have been a 15" plastic culvert but i could only find them in 20' sections and that was way more than i needed. so i backfilled with rock and then about 8" of dirt/clay on top of the rocks.
then i hooked the pump up and ran one garden hose wide open for about 35 min. and then it dried up, i have to wait an hour or two and then i get about another 35 min. the flow is less than i hoped but I was pretty uncomfortable with the hole being deeper than i am tall.
i would really like to use my post hole digger by adding sections of pipe. I just have not figured out the how i am going to do it.
all in all it is an alright well for $20 and 4 or 5 hours of my time.