Well it's been a little over a month of riding with my S40 so I thought I'd give an update.
First off, I'd like to say "thanks everyone!" for all the advice and shared experience on this forum. It's truly been an invaluable source of info and has greatly helped in the research, purchase and fine tuning of my cruzbike. Thank you! Thank you! Thank you!
I think the most dramatic adjustment I've made to the bike is removing the headrest. That's right, after about 100 miles of riding, it became pretty clear I wasn't using it --- except to mount water bottle cages.
Yup, while trying to figure out how to carry water (I could't quite get the 'adding spacers to the existing holes on the back of the seat' to work), I first tried using clamp mounts from REI (only $8.00!) and then Cruzbike mounts ($50.00 -- ouch!).
(This is the REI clamp mount with pump)
Both solutions worked well and even allowed me to carry a pump, but like I said, the headrest had to go.
I ended up drilling new holes a little higher up on the seat for the water bottle cages and that works fine and as you can see from the top pic, I also carry a bottle on the boom. Works great.
I carry a pump, tools, spare tubes, etc. in a fanny pack behind the seat. Seems temporary but works really well too.
To address wheel slip, I've swapped out my conti 4000 28's @ 100 psi for kenda happy medium 35's @ 80psi. Straight off the ride quality smoothed out significantly and slipping reduced especially on loose gravel inclines. I've also been experimenting with leaning forward on the seat while climbing which seems to have some effect, although I'm not sure I have enough experience doing this to have an opinion on the benefits if any.
I also ordered a Thor seat more than a month ago (does it take this long to get?) and honestly I'm not sure I'll be needing it. The stock seat really ain't so bad, especially with the ventisit pad. I'm actually wondering If I made a mistake shelling out the dough for the "upgrade". Oh well. Bikes are my weakness and as you can tell from this post, it probably won't be the last time I do a little overspending in the name of research (that's what I tell my wife).
Anyway, the bike's been a real blast to ride. I look forward to getting on it every day and continue to be amazed at how well it performs, especially since before purchasing the S40, I was all but scared off by some of the negative posts regarding Cruzbikes and MBB on this and other forums. So glad I did't listen!
-Leif