It is my opinion (since it is my blog), that the best practice on the tour is to take just enough full outfits for a single rotation of clean and dirty clothes. Obviously, this includes clothes needed for after the end of day shower and sleeping. The issue is more about volume than weight. No matter how you slice it, the best laid plans will have you filling half a pannier with clothing (unless you pack on top or trailer tour).
I tried touring shorts as a bit of an experiment, having trained comfortably in them. The attraction is that they have pockets, some padding (though not us much as conventional road shorts), and can double as a regular pair of shorts since they look fairly normal. During my Florida to Maryland ride, I wore the touring shorts exclusively through the Florida part of the trip. Although the pockets were convenient for taking my wallet and coins into stores and restaurants, there was just not enough padding for the purpose of being on the bicycle for eight hours each day (again, my opinion). I was constantly fighting butt fatigue. Don't laugh. It was altogether fairly unpleasant. I switched over to the bicycle shorts and my butt was Mr. Happy for the next 1000 miles or so.
Of course, the best laid plans are stupid (see first paragraph). Having switched to bicycling shorts, the lack of pockets became a bit of an issue. It seems I had packed only one shirt with pockets. Two out of every three ride days, I was hand carrying cash and coin into establishments. This is how we learn!
I did do a couple things right, though. The selection of a recessed clip in shoe (vs. the clippity-clop affair associated with most road shoes), allowed me , for example, to walk into a 7-Eleven with dignity (notwithstanding the spandex shorts and funny colored shirts which were not always well understood, particularly in southern Georgia and parts of Virginia). Also, I thought it rather clever to have purchased a pair of cycling glasses with a reading lens in the bottom. This was perfect for my old eyes to see my cycle computer and read my cue sheets on the fly. For those interested, these can be custom purchased in varying magnifications and are surprisingly affordable.
Most evenings I would wash the clothing that I had worn during the day by taking them into the shower with me. After wringing out the items by hand, I would hang them in the bathroom or wherever they could get good air flow. The clothes would not be fully dry by morning, so I would secure them to the rear rack during the ride day and allow the sun to do the rest. On the few occasions that I stayed at a full service hotel, I was able to take advantage of coin-op wahsers and dryers.