Should be 10 hours free from duty if you report for an FDP the next day.

117 says you must have an 8 hour sleep opportunity on any layover. So, if there are rowdy kids in the hallway or the fire alarm goes off in a hotel while you're asleep and they wake you, those are legitimate excuses to call CS and restart your 8 hours.

If all you do on your next duty period is DH, that can be preceded by less than 10 hours of scheduled rest.