One thing that really made a massive difference for me was making a proofing box. It's a large EPS container (similar to the ones that market sellers use) with a seedling heating mat inside. I control it with a cheap (like < $10) thermostat from Amazon. It maintains around 26C quite easily and is pretty efficient. I've never bothered to check the accuracy of the thermostat, but I imagine it's within a degree or two. You can also use it for fermentation, Noma have instructions on how to build one. My only suggestion is don't do what I did and go nuts on the size. You can get away with a much smaller box (e.g. I bake 500g loaves mostly, and I use a 4L graduated polycarbonate container - it's dwarfed by the size of the box).
Temperature control makes an enormous difference. I live in a cold house, hence why I built this. To make things worse, my kitchen has marble worktops. So if you use cold or tepid water and then knead, you end up cooling the dough even more on the counter. It's a bit different with Tartine because you don't really knead the dough, but still - yeast is optimally active around 25C or so and if you have to wait for the dough to come up to temperature, that can easily add an hour or two. So you can control this by measuring the temp of your water and using a climate controlled box (which costs about a tenth of one of those pop-up Broder ones).
I do agree about starter refresh cycles though, as well as what hydration you put in, how much you put in, what exactly the flour is. I don't climate control my starter except during the winter when it sits by the boiler.
Most of the time my routine is identical to yours. Feed the starter overnight Friday, make the dough Saturday morning and bulk it during the day. Refrigerate overnight and bake on Sunday.
I have a Sous Vide rig. I put my dough in a one gallon plastic bucket and that floats inside a small beer cooler with some water in it that the circulator keeps at whatever temperature I want. A dish towel over top ensures the temperature is basically constant top to bottom. Proofing dough to within 0.1C accuracy is ridiculously overkill, but that accuracy comes for free. Works amazingly amazing.
Temperature control makes an enormous difference. I live in a cold house, hence why I built this. To make things worse, my kitchen has marble worktops. So if you use cold or tepid water and then knead, you end up cooling the dough even more on the counter. It's a bit different with Tartine because you don't really knead the dough, but still - yeast is optimally active around 25C or so and if you have to wait for the dough to come up to temperature, that can easily add an hour or two. So you can control this by measuring the temp of your water and using a climate controlled box (which costs about a tenth of one of those pop-up Broder ones).
I do agree about starter refresh cycles though, as well as what hydration you put in, how much you put in, what exactly the flour is. I don't climate control my starter except during the winter when it sits by the boiler.
Most of the time my routine is identical to yours. Feed the starter overnight Friday, make the dough Saturday morning and bulk it during the day. Refrigerate overnight and bake on Sunday.
Strongly recommend watching Chad do it: https://www.youtube.com/watch?v=U4dyWZZVeWI
It answered a lot of questions I had from reading the book.