With tubies you are less likely to pinch flat. When I am riding sew ups, I ride with tools, a pump, and an extra prestretched tire with a few layers of glue already on the base tape. When I flat I just pull off the old tire, mount the new one, inflate, and take it easy on hard turns. its enough to get me home. Takes all of 5 minutes. I am happy with the gatorskin sprinters, though they are not as lively as some of the nicer tires (my personal favorites in terms of ride quality are the vittoria corsa evos. If its any testament to the durability of the gatorskin sprinters, I recently did a race down in Santa Cruz which involved 15 miles of road riding followed by about 25 miles of off road and single track. I had no problems, where a few other riders got taken out by pinching.

If you do go the clincher route, my personal favorites are araya rims. The 1w's and adx 510's build into nice stiff, strong wheels. Mavic is another option, and you may be able to find some nice boxy rims (ma2's?) that would preserve the more classic asthetic of your current rig. Properly built up, they should be just fine for someone of your size.

I have ridden the tufo tubular clinchers and was not particularly excited by them. I found the ride to not be exceptionally different from regular clinchers, and they are a total hassle to mount properly.

If you are still looking for a seatpost, I like the Thompson Elites and Masterpieces. Very adjustable, and have markings on them so you can really dial things in.

coffee is the best. i live off that ****.