Just a note,
With Lawrence Sayre's help, I've added a calculated field stop for every eyepiece to my latest version of the Eyepiece Buyer's guide. I also added a column that will automatically calculate the magnification for every one of the over 1500 eyepieces if you merely type the focal length of your scope in mm into the column header for that column. If you change scopes, merely type in a new focal length and the chart will recalculate every eyepiece.
If anyone would like a copy of that spreadsheet before it's posted here on CN, send your e-mail address to me in a private message. Give me a day to respond since I work long hours.
Don