Grabbed this from the Hearts kickback board.
It's simple enough there are 5 places available allocated thus
SPL 1st ->Champions League Group Stage
SPL 2nd ->Champions League 3rd Qualifier
Cup Winners ->Europa League 4th Qualifying round
SPL 3rd ->Europa League 3rd Qualifying round
SPL 4th->Europa League 2nd Qualifying round
If Ross county win the cup then they will go into the 4th qualifying round and no alterations will be needed.
If Dundee United win the cup and finish 3rd then they will go into the 4th qualifying round, the 4th place team will go into the 3rd round and the 5th place team will take their place in the 2nd qualifying round
SPL 1st, Rangers->Champions League Group Stage
SPL 2nd, Celtic ->Champions League 3rd Qualifier
Cup Winners, Dundee United ->Europa League 4th Qualifying round
SPL 4th, ? ->Europa League 3rd Qualifying round
SPL 5th-? >Europa League 2nd Qualifying round
If Dundee United win the cup and finish 2nd then they will go into the Champions League 3rd Qualifier instead of taking the cup winners place in the Europa League, Ross County will go into the Europa League 2nd Qualifying round, The 3rd place team will take the Europa League 4th Qualifying round spot and the 4th place team will move to
Europa League 3rd Qualifying round.
SPL 1st, Rangers->Champions League Group Stage
SPL 2nd, Dundee United ->Champions League 3rd Qualifier
SPL 3rd, Celtic ->Europa League 4th Qualifying round
SPL 4th,? ->Europa League 3rd Qualifying round
Cup Runners Up, Ross County->Europa League 2nd Qualifying round