100 psi in a 35mm tire is incredibly overinflated....don't do that unless you want a harsh ride and no benefit to your larger tires.
I weigh 175 and when I ran 28's I put maybe 95-100 psi in the rear and 90 psi in the front....no pinch flats, decently comfortable. My current 37's I run 65 psi in the rear and 60 psi up front....very nice ride.
Are there any bombproof tyres that will be more comfortable? (if it comes to it, I would prefer more puncture protection over comfort)
If this is the case, just run armadillos in whatever size you want and pump them up to the max psi listed on the sidewall of the tire.
People have argued with me on this, but my opinion is that larger tires run at low psi offer FAR FAR more comfort and also additional puncture protection. Most flats I have fixed at bike shops are from people using crappy air pumps and not running the right pressure (pinch flats).
There really is no reason to run 23mm tires unless you are racing, or doing some intense training....if so, go for it. But for commuting and general riding or touring, there is no way to make 23's as comfortable as would be ideal on crappy streets....if you run psi lower you will just bottom out the rims.