Hi Mark,
I would disagree a bit on taking TDS measurements as having value given that we all do not have access to mass spectrometers. Measuring TDS at 10s intervals and then compare to a “standard” coffee extraction model of compounds over time could yield a relationship between TDS and effectives of extracting a particular compound correlating over time. Then pour method could be adjusted to emphasize particular compounds at different points.
I do not use the same pour velocity throughout my pulse brews. I am more aggressive in the beginning and very little agitation middle and toward the end to extend my “runway” before I run into bitter notes. My own way of “managing” flavor compounds in the brew.
So, here is a kickstarter, Create a tds IoT meter device that has a probe into dripper, then send telematics to data lake for big data analysis! 
Ah the magic of superfines… Sette generates a very significant amount of fines when grinding for pourover. It is a known behavior of the Sette, many back and forth emails with support. What is a little different, is that even sifting < 250u does not remove super fines. Hypothesis is that these are statically attached to the larger grinds.
So what happens, is that after sifting, the brew still will not drawdown in a reasonable time. The paper filter clogs almost immediately even after sifting. You can see a thin super fine silt around the paper that very surprising restricts water flow. Fines less than <250u are roughly 10% of the grind weight. The actual superfines are not measurable, so I don’t know what their percentage is of weight, likely a very, very small amount.
So, the Sette is not usable for brewing with most methods even with the coarse burr replacement. You CAN use it, just us e a V60, with small dose like the usual 12g but with less water maybe 175-180. 200g of water takes to long and brew goes bitter. Doesn’t matter the grind size so much, superfines will be there along with the fines. Nature of the design.
Works great for Espresso!
Preciso never has this issue, longest brew time was 4minutes and that was with a particularly difficult Ethiopian. Sette at times would never finish, just pool up into mud.
Paper filter, I used standard Hario for v60 though there was this fake brand where brew times were greatly extended. I threw those away. I use Gino filters sometimes for Kalita to extend brew times for dark roasts. Extends about 20% in time and then I drop coffee:water ratio very low. It’s magic for dark roasts.
Target brew times for me generally are 2:45 to 3:10 for V60 and 3:10 to 3:45 for Kalita with standard filters. All depending on coffee beans as you describe. I do not have good luck with longer pours than that timewise.