Harmonic base verification
To verify your harmonic base with F#, your personal fundamental pitch, turn on the F# drone loop. Take a moment to tune in.
With the F# drone running, one at a time and with a moment of listening just to the fundamental drone in between, leisurely try out the two pitches below as many times as you like. Determine which one of the two, B or C#, suits you better in the context of the F# drone.
By choosing C# over B or both equally, you verify F#, your personal fundamental pitch, to be the fundamental for your individual tonalities, forming their harmonic base with C# as their quint. But if you clearly chose B over C#, you can proceed with B as fundamental for your individual tonalities, forming their harmonic base with F#, your personal fundamental, as their quint.
Reference loops
Turn off any running loop before starting another, or they may sound simultaneously.
F# with C#
B with F#
Explanation
The harmonic base of a tonality is its fundamental together with its quint (fifth), the first overtone or harmonic that is not an octave of the fundamental. F#, your chosen fundamental pitch, may well be the fundamental of your individual tonalities, together with C# as quint. However, if verifying your harmonic base you chose B over C#, through the miracle of nature, B becomes the fundamental of your individual tonalities, and your chosen personal fundamental pitch becomes their quint.