To be honest, for a single bowl, it's not necessary to be formal! For example, the same singing bowl evaluated by a tuner with the note D at 440 Hz will give (with this same tuner) a D# at 432 Hz. We just change the calibration, but it remains the same quartz instrument. However, for a set of crystal bowls, it's quite different! The note A in the 3rd octave (reference note) being tuned to 432 Hz, all other notes will be tuned to 432. And there will be a real difference with note intervals that are lighter, more airy as they are slightly sharper.
The Immaculate crystal bowls, in 432 Hz, will therefore be slightly sharper by almost 1/2 tone.
Read the blog article on the subject
In summary, unless you are a musician or convinced that the 432 Hz frequency is the best, the ESSENTIAL IS THE CRYSTALLINE ENERGY. It is what purifies, clarifies, or raises the vibrational rate of the Living. The rest is a matter of personal preference and stock.