I followed the same recipe as in attempt no. 42, baking at 250° F for 20 minutes, rotating the tray, and then another 10 minutes. The first tray was underdone, so I added 90 seconds of baking time to the the second tray, which came out perfectly.
In summary, they piped out nicely (2 points, as per my scoring system), they all came off the Silpat (3 points since the first batch stuck a little), they look like macaron (4 points), and they’re delicious (1½ points, because they are a little too chewy). I win.