Please correct me if I'm misguided here:

I've been thinking lately that I would love to have more temperature control with my newly acquired Chemex; here's the strategy I've adopted —in a truly perfection-driven fashion that may be excessive.

Preface:
I picked up a Nissan thermos carafe off eBay —the large volume type used for half-&-half.
I scored a sweet-ass, nearly instant responding digital thermometer from my fiance's boss, a 5-star restaurant owner.
I use a early 1900's-era Zassenhaus 156-style knee mill with nearly flawless burrs that produces a brilliant grind —seems it was kept as an ornate piece— that I scored from De Profundis.com

What I've been doing is boiling my water at a rolling boil, transferring 1/2 my 212°f water into my pre-heated Nissan thermos where it will keep in the 212°-210°f range —using the other 1/2 to rinse my filter and pre-heat my Chemex beaker.

Now, what I've been doing is portioning off the water I intend for each interval of pouring into a steaming pitcher —onto a tared-off gram scale— with my thermometer inserted, from my thermos of 212°-210°f range water —I find that if I'm quick with creating a good seal with the thermos lid the water will hold at 211°f± for quite some time.
Given a few moments —and provided you've pre-heated your steaming pitcher— once you've slowly come down in temp to 200°f it will hold there long enough for your initial pour —and subsequent pours there after.

I imagine one could allow the water to come down in temp. further before pouring into a thermos, but I like a larger margin to allow for more potential temp. control —and it seems to jibe well with the time-conscious pouring technique required for the Chemex method.

Working out the timing only took me three goes before I had a consistent work-flow and was able to repeat my results time-&-time-again.

Personally, I think it sounds like way too much work, but -- hey! -- if it works for you, that's what counts.

It must seem like a PITA on paper. But really it's just a bit more pouring from one container to the next. I like that it opens the door to discovering which temperature best compliments which coffee I'm brewing.

I had read someone posit on another board that it may be the fluctuation of water temperature throughout the pour that lends the coffee produced some of its character; for some reason that struck me as being irksome, as one would only be able to hope for an approximation of the ideal result with only one solid, repeatable variable to adjust —grind.

Maybe I'm just subconsciously yearning for a Technivorm and won't allow myself to come to that conclusion out of fear of placing another pricey toy in the kitchen for the fiance to roll her eyes at.

Me and my fiance are planning to do just such a blind tasting soon.
I have done an impromptu 1-to-1 blind tasting between different
brewing temps with the same coffee; and while I can't say much
definitively, there does seem to be a difference that approaches
more desirable characteristics between different water temps.

It certainly has me intrigued and may open up new potential —
at the negligible cost of seeming a bit persnickety.

Although I have not done blind comparisons, over the last year or so I have found that I get the clearest most focused flavor by keeping the temperature in a narrow range while brewing. I do this by brewing coffee over a flame and using a probe thermometer. I wouldn't argue that this 'clear' flavor profile is the best or only way to drink coffee, but it's the only way I've found to give me cups of coffee which make me happy in a way that seems to transcend mere flavor.

Temperature control has been the thing that kept me away from the Chemex in the past, kudos for figuring out a way to overcome that!

I've since dropped the pouring into pitchers and started doing the following:

I rinse the filter and pre-heat the glass, pouring that water back out and into my thermos to pre-heat the thermal carafe; once my second kettle (I bought a second) comes up to boil, I let it go 10-15 seconds off the boil, empty my thermos, pour my brew water into the thermal carafe, drop my thermometer in the mouth of my thermos and grind my coffee while the water temp. comes down to where I want it. Once I hit the range I want, estimating a small variance, I cap my thermal carafe and pour from it —I make sure to only open the threads of the cap while pouring, as to keep my water temp as stable as possible.

My fiance and I did do a 1:2 blind tasting recently as another member suggested and we both agree that the temp. controlled cup is favorable —YMMV. The differences aren't night & day, but some aspects of the coffees we've been using —an Etho. Harar, a Yemen Mokha Sharasi, an Indian Jasmine Estate and some Yirg.— were definitely affected favorably. Also, it's really nice to have the option of dialing in which area of the temp. spectrum best suits which coffee and being able to repeat the results, consistently.

I just got a Pino Digital Kettle and set it to 205*. It seems to work perfectly for pour over and its also been great to add just off boiling water to my vac pot. I have an aeropress coming in the mail and I expect the new kettle to work nicely at the recommended 175* temperature. My wife has used it at this lower temperature to brew her tea and commented that it is both easy to use and makes a nice cup.

I've been meaning to get an electric kettle, myself. I have to wonder how well these hold their temp. once the heating element has kicked off. Or do they cycle on and off with a thermostat?

The Pino cycles on and off as expected. I was however, a bit surprised to see it go up to boiling temperature before settling down to 175* when I had it set for a lower temperature. Once at equilibrium or steady state it seems to have a reasonable range claimed to be +/- 3% around the desired (set) temperture. It's certainly not as tight as a PID control but acceptable for the job at hand.