Just a quick comment on the OFPF technique. It can be too much of a stretch for even seasoned players when used on the lower frets (1-5). By all means, experiment with the technique further up on the neck if you wish, then later on, when your hands begin to adapt, start moving down gradually. Even then, some still find it too much of a stretch lower down. If it feels uncomfortable or causes any pain or strain, then use fingers 1&4 on the lower frets.
The "Bass Method" book that was recommended talks about this at the early stages, and generally recommends using index and pinkie on the lower frets.
Best of luck with it.