Basically you seem to be saying you don't need a lot of heavy clothing to keep warm! An R1 and Houdini are pretty minimal. Your chart is supported by my own experience in summer hiking to the High Sierra Camps in Yosemite (near Tuolumne), although I have some variations noted below.
Here are my personal variations:
I never hike in shorts and short sleeves - too much sun exposure for my taste. I use a sun umbrella from Go-Lite to keep the sun off me. This also doubles up as rain protection in a summer shower. I wear a long sleeve, silkweight Patagonia crew neck tee shirt (I think they call this Capilene 1 now). For pants I wear long pants, light Supplex nylon pants from Ex Officio, but hemmed high, about the length of knickers - to just cover the tops of my socks. This lets the air circulate over my legs. The long sleeve tee shirt is theoretically hotter than a short sleeve, but with the umbrella most of the heat is kept off me so it balances out. The "hot spot" I have is under the pack, but I try to use a Breeze from Go Lite and just shift it around to let one half or the other of my back dry out. I've been tempted to try one of the vent panel backpacks, but they are pricey.
The preceding outfit is plenty to keep me warm; on a summer high sierra hike, the only time I need to add anything is heading early out of camp, at dawn, when a nylon windshirt helps - I like the old, discontinued Wild Things Gear nylon windshirt, it isn't too hot.
If temperatures have been trending cooler, I will wear a zip neck, lightweight (Capilene 2, nowadays) long sleeve as my base layer, and back it up with either a Capilene short sleeve, crew neck tee shirt worn over in lieu of a vest, or a tank top Capilene (they have these from time to time). Finally, the windshirt. As you noted, it doesn't take much to increment the comfort level back up. If I am in an urban environment and its cold, each incremental layer has to be a lot thicker, but when I am hiking the incremental levels are a lot thinner - and the "warmth" generated by the higher metabolic level triggered by hiking tends to carry through after I reach camp, at leas for a while.
I end up carrying a second windshirt, a Houdini, as my rain gear. I try not to wear this unless it is raining, to preserve its water repellency. It isn't perfectly waterproof, but I follow the theory that while hiking I'll just be evaporating off any wet through anyway. This approach might not work in the fall in New England, but it's been fine so far at Yosemite.
I end up carrying a THIRD windshirt (good thing these are light!) as a "vapor barrier" for sleeping. I use one of the original Patagonia Dragonflys, notorious for their poor breathing, which in this context is a big help. It has a hood, and I wear this over my head, with or without a watch cap. I find the Go Lite Snow Cap a little hot in summer.
The one part of the equation I haven't nailed yet, is what to wear to bed to "up" the temperature rating of my quilt. I like to wear enough go to sleep with the quilt just over my legs, and then adjust the quilt up higher as it cools off during the night.
Quite frankly, the R1 hoody sounds very appealing as the "missing link" in my kit. It would obviate the need for a watch cap and Snow Cap; it looks good at the dinner table; and I could wear it under my windshirt around camp in a drizzle, or over the windshirt when sleeping (for the vapor barrier effect). So far I have been experimenting with synthetic fill vests and pullovers, and with heavier Polarguard like the Body Rug from Patagonia (a very high loft, equivalent I suspect to 300 but lighter in weight).
The only conclusion I have come to over five seasons of hiking, is that you need a different "kit" and approach for "active" trips and "take it easy" trips.
If you are going to be very active, with little time spent idling around camp outside of a sleeping bag, then every item of clothing needs to be much thinner. Silkweight for baselayer, R1 for insulation, a Micropuff Pullover for extreme insulation.
If you are going to go to Camp Curry in the dead of winter and rent an unheated tent cabin - as I have done - every item of clothing needs to be MUCH thicker - mid-weight zip neck tee, R2, down parka or thick synthetic parka. Otherwise the cold weather coupled with the inactivity will gradually suck the heat out of you and leave you miserable.
In any setting, though, layers seem infinitely better than just wearing a tee shirt for the sunny hike and carrying a thick down parka for camp, which is the main point of the post, I suspect.
Still, I like the elegant simplicity - lighweight baselayer, midweight (R1) hoody, windshirt. That's a slick analysis.