I personally see Drift happening sometime after Megatron Origins but before most other stuff, because Dai Atlas is there... and he was killed by Shockwave shortly after he underwent empurata and shadowplay. And as you said, Metalhawk was there too.

It's just a nightmare to try to sort out (which is why I've never tried to do it before, plus it was just easier to sort them in publication order as I collect them, but then it kinda feels disjointed when you go back to read them again). Gah.