Grand Slam of Darts betting tips Luke Humphries to win - 3/1 BoyleSports Michael Smith to win - 22/1 SpreadEx Grand Slam of Darts betting preview This year’s Grand Slam of Darts is looking tasty. Grand Slam of Darts prediction 1: Luke Humphries to win - 3/1 BoyleSports Grand Slam of Darts betting tips: Smith to right his wrongs Smith’s …