I am going to be installing a six foot tea fof two Kohler in a upstairs bath remodel. What is the proper way to support it? I,m concerned about the weight. I figure that the tub when full will weigh 600 to 700 lbs. If possible I would like to spread this weight over as many rafters as possible. My subfloor is three quarter t+g over 2 by 10,s. This is going to be an undermount install with the surround extending twelve inches at the drain end and twenty four inches at the other end. Any thoughts? Thanks, Steve