Somatic Vision

Except for aiming for higher LF is there more information that I can get from the power spectrum? For example is there a difference between HF that is scattered and one that is concentrated in one bar, say 0.2Hz?

The interpretation of the power spectrum is something you should research or ask your biofeedback teacher about. This is a complex topic with different interpretations, and probably is something that could relate to specific conditions.

That said, there are some straight forward differences between a concentrated HF in a single bar, and that with say, 3 close bars. A concentrated HF means that your heart rate is probably precisely following your breathing, and that your breathing is also precise (reliably the same) but what that means is something you'll need to decide or ask about.