It's not certain if those, who voted TR would automatically vote for Taft.
This is assuming they did. Much of the reason Wilson won was because Roosevelt and Taft split the Republican vote. (Much like Nixon's first election in 1968 owed itself in part to Wallace and Humphrey splitting the Democratic vote.)
Well it has to be wondered if many Dixiecrats would vote for Humphrey, "The Happy Warrior". I mean, the Deep South had already ditched the Dems in 1964, and 1960 showed that both Republicans and faithless electors could win Southern states.