16" D3 is a thin walled bowl. It is nice if you want to get the bowl to sing and then let it ring out. The thin wall leads to the mallet chattering from the vibration of the bowl when you keep the mallet on the bowl for a long time.
Despite this problem, I do enjoy playing the 16" low D3. I just let it ring out and then as it quietens I touch it for a moment and then let her sing again. Can't get enough of this low D3.
If you plan to keep your mallet on it, and play it like a drone, then you might want to consider the 18" or 20" D3 when available. However it is rare for us tome come across larger perfect pitch D3 bowls. I have located only 7 in the past 3 years.
If you decide you like the deeper tones of the D3, you might consider adding G3 for grounding tones (Perfect 4th), A3 for total relaxation (Perfect 5th) or B3 for expanding tones (Major 6th). Or you might decide to add notes from the much higher octave to expand your set. Call and I can help you pick out the notes if you need help.
Not sure what note is the lowest in the third octave?
This is the order of the crystal singing bowls, lowest to highest in the third octave. C3, C#3, D3, D#3, E3, F3, F#3, G3, G#3, A3, A#3, B3