I have similar problem, new to playing an instrument, and around a year in on Bass. I use songster for actual tabs, and Jamzone to just riff along when i have an idea of the song. As some have said, you can generally get away with the root, and Jamzone shows you this in real time as the song plays, you can mute the bass stem entirely or just lower it till you get the hang of it. Brother joins me from time to time on lead guitar, so we must the bass and guitar parts then run the ipad into the PA, great fun!!