Alexi mentioned the
sport-touring-dot-net sight that has the info on pillion riding. Great info, but you may need to edit it down a bit. My wife read through it and she's about the best passenger I've ever had on the back of a bike.
BTW, I just asked her if she uses the rear grab rails at all, and I was very surprised to hear that she does!? I put a back rest on the bike for her, and just assumed that she didn't use the grab rails, but she said that she uses both the grab rails and the back rest. She also said that she wouldn't even consider riding pillion anymore without the backrest. So there ya go - info worth what ya paid for it.
Also, she really likes the Cee Baily +4+4 windshield. If we are going faster than about 65, she tells me over the intercom to raise the windshield. Makes it alot quieter for her also she says.