Initially, my choice of the 1300 came down to liquid cooling and price. In the Phoenix area I felt liquid-cooled was a must for our summers. And in 7/2010 I could get a new '09 1300 cheaper than either a new '09 950 or 1100, much less the 2010's. I had returned to riding after a 25+ year hiatus and first got a 650R Ninja. But after my last back surgeries I (mistakenly) thought a cruiser would work better for my back, hence the new 1300.
For the size of the bike I find that it is surprisingly agile. A sport bike by no means, but it does handle well. Power is more than adequate for your intended needs. I am at 240 lbs. and performance is pretty strong, having done the airbox mod and adding a slip-on exhaust. Mine is currently set up for solo riding at this time. I think you will find the higher stock hp./torque of the 1300 to be a benefit for two-up travels.
One concern I do have about the 1300 vs. the 950 or 1100 though is the availibility of aftermarket "stuff". While you can get most of the things one may often add-on to the bike (seats, bags, bars, racks, etc.) the variety is often lacking. Though a newer design/model the 950 seems to have a larger selection of accessories out there.
Another downside of the 1300 may be insurance costs. It may be cheaper to insure the 950 than the 1300. Some companies don't seem to regard the fact that it is a fairly heavy slow cruiser- they just look at that 1300cc number and think high output speed demon bike.
From your description of your intended use of the bike, I think you would be very happy with the 1300.