One thing I have yet to see mentioned on this thread. If you and your brother don't yet have them seriously consider some form of Bluetooth communicators and a way to charge them for the ride. Wife and I have started doing some rallying and find the ability to talk to each other priceless. The simple things like bathroom breaks and gas stops or heaven forbid mechanical issues need to be communicated to your riding partner.
On my '07 I was normally riding with the seat in the low position all of the time. It was recommended to me that on long trips I try to ride with it in the high position. While it makes flat footing impossible for me it made a huge difference in rider comfort on the slab. Keeps your thighs and butt off the hard parts underneath the seat.
You can do this!
I can echo this post wholeheartedly after SWFOG, I have a Sena10 and used it to link my phone, music, GPS etc. But never linked with another rider, because I have been limited to riding with some locals, who are mostly pirates, and rarely wear helmets... (thats another discussion altogether and usually gets me in trouble) During SWFOG I finally got to link with other riders. WOW. It changes the ride, and for the better! If you don't get the Sena, get some other way to communicate while underway! You will not be dissapointed and then wonder how you ever did without this wonderful device. (I know, I know, I late to the party. And have been called worse than a slow learner, but I make up for it in perseverance.)
The higher seat position does make a difference as well, and for the better. I did not think I would like it, but it does help.
Oh, and plus one on the hydration thing. I put a Geigerrig in the cooler behind me and run the tube under my arm and then attach it to a retractable key ring thing, I like to use the passenger foot rests sometimes for my heels and the pegs for my toes so I cannot use the peg mounted thermos set up.