Yeah your probably right about using 6 joints. I would be able to create a smoother curve if I placed one every 3-4 inches.
I was going to put about 15-20 lbs of weight in the base to help with the weight of the LCD. Since I'm going to use bondo to make it look like the pelvic bone was dug out of the ground like a fossil I can cover the weight with bondo and create more of a flat stable bottom. Or if the joints work go enough then curve the spine forward to have the pelvic bone rest right below if not a little forward of the screen to help balance out the weight of the LCD.