Far out John. Do you and your son eat nails for breakfast!
Again, great effort to you both.
Ok, firstly sorry for hijaking the thread.
2ndly, and I hope this doesn't upset others, but SSing ain't that big a deal! I say ride what you enjoy. I'm a simple guy and SSing just pushes my buttons!
Once you reach a resonable level of fitness I'm sure your stead won't make that big a difference to your times. Can't imaging I'd be any quicker on 27 gears than my SS in this event. In fact I think the KO is perfectly suited to a SS compared to 'flatter' events (well for mug punters like me anyway). Only thing to remember is that when the going gets tough (as in your knackered) thers's no gears to hide behind, hence the need for training (or anti-training!).
For me it goes deeper.
I use to ride a full sus., 27 speed which I loved but always ended up with sore knees. Almost gave up MTBing!! Took a Carver 96er SS for a test ride and ended up riding 60km that day, about double the distance I'd ever ridden B4. I was hooked!....and no sore knees..ever!! even after this recent trip...
http://www.rotorburn.com/forums/showthread.php?208953-The-Self-Sufficient-Bike-Camping-Thread/page48
Also I believe that SSing is so much better as a full body workout. Most SSers I know don't come packaged with huge (or even noticeable) calf muscles. Why? Because all of your body is involved with the experience not just the legs. On a tough ride I generally find the upper body feels it more than the legs, and for me, thats a good thing.
Last year I watched a 'chick' ride the whole of 'Sledgehammer'. I was totally impressed! But for most SSers thats never going to happen. If you can't handle that idea then SSings probably not for some. Mate of ours once said he hates walking so he'd never try SSing, and we still ride with him!!
So go give it a fair 'ol crack and see if it works for you. I'd hate to think the whole SSing thing becomes a 'them-and-us' contest. After all, its about the journey.
John