I unlocked this on medium, for reference there is a pause in playing just under halfway through the song - that is approx. 455 notes in as I fluffed it coming back in after the break. So really it isn't that hard to do at all (I've never played drums and only been playing them 1.5 days, OK I am competent pianist though but I reckon that nobody should find this awkward on medium after a lil bit of practice, it's mostly the same beat all the way through).
On medium when you come back in after the break you are only single kicking the bass drum for a few bars before you start to double kick again, this caught me out a couple of times, it might for you as well. 4th run through and I hooked together 759 notes before my right leg gave up on me, you can probably afford to flunk the first verse and still hook this one up after that.
Achievement unlocks once the song has finished, not during play.