harmony 650, flirc se and kodi/tvheadend

[loonylion]

Hi, My parents have a harmony 650, a flirc se and a htpc running kodi and a tvheadend client plugin. I need to make the remote control the kodi box in as fully featured a way as possible, including powering the machine on if it isnt already, launching kodi via a remote button (the machine has remote clients and also wakes itself to record tv shows when necessary, so may already be on), standard tv controls within kodi and the ability to exit kodi (NOT shutdown the machine). I've found loads of threads about harmony and all have different suggestions, so I'd like to know if there's a definitive guide to achieving what I need. My parents. while somewhat IT literate, are getting on a bit and they want a tv remote style experience.

any advice?