Am I the only one using a projection print scale?
http://www.freestylephoto.biz/41621-...on-Print-Scale

Pick an F top (usually F11 here), slap that on the spot you're most concerned about, or just smack in the middle, and pop the timer on for a min. When it's processed you can read the correct exposure time off the wedge you like the best. I've even used it to split grade. Seems to work for me so far.