A great explanation of a lot of things, but this looks wrong to me: "To put a number on it: surgical masks on the sick person reduce cold & flu viruses in aerosols by 70%. Reducing transmissions by 70% would be as large an impact as a lockdown!"

Reducing the amount of virus in aerosols won't reduce the number of infections by the same amount. If a cough produces ten times the infective dose, then with the mask that's still three times.

Masks are still likely to help (and maybe having a smaller dose will make the disease milder if someone does catch the virus), but it's not possible to make a statement like this about the effect on R.