> if you have twice as long infectious and half the R 0 you'll get exactly the same growth rate (7m15)

uh... no. (I am not an epidemiologist, but neither is he, so...)

R is an estimate of the total infections one person will cause. So if you're infected for twice as long, and R remains the same, then the growth rate will be halved. If you also halve R, the growth rate will also be halved.

I don't believe he understands what he's talking about.