I'm going to make my first all grain pumpkin beer. Here's the recipe http://www.brewmorebeer.com/pumpkin-ale/
He doesn't give the amount of water to use for purging and sparging? Is the rule of thumb 1 quart of water per lb of grain for both? I don't remember, sorry!
By purging do you mean mashing?
I mash with 1 or 1.25 quarts per lb. Add that amount of water up and figure 0.1 gallons water is lost by absorption for each lb of grain. Then sparge with the amount that will give you the correct preboil volume.