I'm looking for feedback on use of the thumb versus index finger in roll patterns. I've been playing about a year, almost exclusively with a forward-backward roll on songs where the thumb alternates between 3rd, 4th and 5th strings, keeping a steady syncopation rythym thing going. It works well for songs like Mamma don't allow, Worried Man, and a bunch of others. But I know I need to add more rolls for more variety and other songs.
My question is, is it a bad habit to use the thumb regularly on the third string, instead of the index finger? Janet Davis in Spitting the Licks indicates regular use of the index finger for the 3rd and 4th strings for a forward roll. I get a stronger sound with the thumb. My inclination is to use the thumb, but like I say, not wanting to learn a bad habit that will need to be unlearned later on.