My background in motorcycling and age are very similar to yours.
I've been riding for ~40+years and I'm 53.
Anyway I can't give you an exact answer to your question, but I can give you a little info to help you decide. Both motorcycles are good dependable motorcycles. I don't own a 950 but I've read a number of reviews about them and I owned a Kawasaki Vulcan 900 custom before I bought the 1300 (for size comparison). The first thing to consider is what type of riding you do most of the time, and of course what looks you prefer. Personally, I like the "Custom" look as opposed to the retro "Classic" look. The 950 falls more on the custom looks than the 1300. I bought the 1300 because I wanted a bigger bike that was more comfortable for long rides and 2-up riding. I also had a preference for fuel injection and water cooling. The 950 is fuel injected but not water cooled. One thing I'd look at is the weights of the bike and are you going to be doing more in town riding or highway riding. The 950 is probably (don't know for sure) a little lighter and may be better suited for local traffic. This does not mean it's not suited for highway use, it will cruise fine on the highway at illegal speeds with no problem.
I would put some of this info in reference to the 1100. The 950 probably is similar or maybe a little less performance than your 1100. The 1300 is a much peaker peformance motor, although it has plenty of lower end, it likes to wind up a little more than the 950 or 1100. The 1300 also has a 5 gear overdrive which lowers the rpms at highway speeds. The 1100 5th gear is about the same ratio as the 1300 4th gear, so you won't feel like the motor is winding as high at highway speeds. I could probably go on with this, but this might help you to figure out what you want.
As another option, Star came out with the Stryker this year, it is a Custom with the 1300 motor on it.
Here's a couple of links that would be useful info about the Vstar 1300:
Someone on the Vstar1300riders link below has over 100,000 on a 2007 1300.