As for Strouhal number, you have to figure out the value of 'S' to apply to the equation. The value I came up with was S=0.12 but this was before video and so not accurate. Video is your friend as the cycles are too fast to count and operate a timer at the same time.
'S' is a function of lip width, distance and time.
Once you have a value for 'S', you can apply this to different widths to calculate the new frequency, or the retrieval speed to achieve a specific frequency.
If you do a TU search for Strouhal, I am sure I have posted about this before.
Dave