So I tried the alternating workout again (I have to think of a name for this workout). A kilo at faster than MP, then a kilo at MP, etc.
It went like this: 3:51/4:19/3:56/4:17/4:03/4:10. Only 6k because I will run 40k tomorrow.
It went pretty well. I like this workout, it is nice and challenging.
That is to say, it requires discipline, both to push yourself to the faster pace, and to try to hit the MP kilos correctly (which is not easy). As Gebresailesse told Chiba-san (and a few other people at the Great Australian Run press conference), discipline is the key to success in distance running. That's why I like to do most of my workouts alone, including some hard ones. To build mental toughness, not just physical toughness.
10.7k 54 minutes
Weather: 10°, sunny
My knee did not hurt at all, which was nice.