Hm, I thought the ADR finder sites were shut down after last years fiasco.
Anyway, OP, I don't think you answered the question of if you were using the Magical Express or not. If you are, then heed the caution of others. There is no set "route" for the DME buses. You could be the first or last stop, and if your plane is late or DME is being held up, you'll be SOL.
So, I'll say this... It's doable, but with so many variables in play, it's not something I'd chance missing. If you're able to back things up an hour or so, that'd be better to give you some breathing room.