I have the stock seat and am usually searching for a more comfortable position after an hr or so, I cant really recommend the Touring seat because I haven't tried it.
My wife is 5'2" and is very happy with the back rest and leg room. She says the ride is far superior to my previous ride. (H.D Road King)
The suspension is set up perfectly the way it is, I'm still riding it the way it came set up from the factory.
I'm sorry I dint know the max pay load.
Have you taken one for a test ride yet?