Here is another 'Reloading Quantities' Table I have found indispensable; shows the # of reloads per 25lb bag for a wide range of payload weights; # of loads per lb of powder by graduating grain amounts, etc.:http://www.imrpowder.com/data/shotshell ... hp#CHILLED
I converted it to MS Word and added a row showing the "# of boxes per 25lb bag" for payload weights from 5/8 to 1oz:
Weight Ounces 5/8 3/4 7/8 1
Boxes @ 25 Lb. 26 21 18 16
Along with the earlier thread thoughtfully posted by Calisto (and titled, The "Shot Size Table" on Shotgun World), these tables take a lot of the guesswork out of getting started in reloading. Probably make a good sticky (hint! ;-)
Best o' success!