Need-Electrostatic Loudspeaker Design Cookbook

Google is your friend...

I typed in "electrostatic loudspeaker design cookbook" and got pages of places to get a copy. You might also want to talk to Roger.
If you would like a great recommendation buy a used set of Acoustat one plus one's or two plus two's. Enjoy them then modify them and then build some brand new panels this will save you more time and money than you can ever know. The end results will be astounding for peanuts.