I just completed a tour on my old mountain bike and decided to look into getting a road bike for next tour.
In the mountain bike world - I am considered a "Clydesdale" (6'1" 220pounds).
LBS has array of road bikes and as many opinions as sales people. Articles on this and other web sites really don't discuss the tires and sizing. Sheldon Brown has super articles on tires, but no real info about how to pick and choose. It is a great place to learn all of the jargon - so you sound like you know what you are talking about at the LBS.
I have already figured out that the bike I buy will be a set of compromises - gearing, tires, bars (I am 67 and there is no way I can lay over bars 10 hours a day for a tour), ...
Thought I would start with tires. All of LBS models have super skinny high pressure tires that just don't look like they would survive on a long tour. I am sold on the Specialized Kevlar Armadillo tires as my current set has about 1400 or 1500 miles with no flats.
What size tires work best for folks who approximate my environment? I'm not sure whether picking a specific bike locks me in on the tire sizing issue. I'm sure there are basics such as which rim sizes will work on what bike, but not sure how much leeway one has in deciding these things.
Any thoughts - opinions - pointers to web sites, etc. will be appreciated. This is first step in what I think will take a while to cut and paste recommendations together to lead to a purchase.