Possible Clues:

• Maybe twenty winks before noon, or fewer than that?
• Six
• Number of the teams in the Six Nations, for instance, get fair share that's key to the rest and has a bearing
• Barely any sleep before noon or six?
• Henry, once upon a time in Ireland, found eastern discipline with a fair share from Baker
• A few that could be making fuss or providing Buddhist school
• Henry, long ago in Ireland, came across eastern discipline in Six Nations, for instance
• The briefest of sleeps at noon or six
• This ado - or Zen - is for 1 across, all the same