Thank you each and all for your great comments!
Here's a couple more shots of the chawan. None with matcha tho - gonna need some advice on this bowl, it's definitely gonna need special care and attention for use. I actually really need some advice from you all on how to proceed with this chawan (and I LOVE this bowl!).
Pics 1st...
shot from opposite side:
macro shot of rim - note the lack of glazing at rim:

(click to enlarge for detail)
macro of interior (area of my greatest concern/need for advice):

(again, click to enlarge for detail)
In the last macro of interior - note the small holes in the glaze. This concerns me (pockets where tea residue can build up?) (also the possibility that the vitrified/crystallized material could break away and be consumed?

).
The feel (to the touch) of the chadamari area is grainy/sandy - and to me this sometimes translates as porous? (thus concern for any kind of leaching?)
Finally - as is usual with any new chawan, I soaked the bowl overnight in tap water. After a couple hours into the soak, there was a very slight smell of "clay dust" or "smoke" or "ash" depending on who is describing it - to me it smells like "clay dust". This odor disappeared after the 2nd soaking, which I began just before bed - total soaking time less than 24 hours. I wanted to use the bowl this morning, so I pre-warmed with hot tap water before adding the hotter stuff from the kettle. Even still, something occurred that I've never experienced with any teaware before! When I added the first kettle water (which was actually 176*) - the bowl made faint sizzling and almost crackling sounds - but no changes of any kind occurred in the surfaces. The sound faded and settled and quieted. So I added phase 3 water at 180*. The singing chawan began to serenade me anew! Totally concerned about this, I pondered, wrestled with my keen desire to use the bowl, finally emptied it of the water, and set it aside to dry. I decided to check in here for advice on this.
(btw, I haven't contacted Jayzo yet to ask him about this - other than my initial contact to inquire about the chadamari surface and possible treatment... he suggested a thick rice water soak. Concerned about the odor of rice water, I replied asking about cornstarch - no reply as of yet.
I will email him again about this sound and my concerns - but thought I'd check in here with my TC friends first in hopes that I might have some good information from which to proceed).
I wonder if continued exposure to pre-warming and warming will finally calm this bowl into silence? Of course I am hopeful of this.
all my Thanks for any experienced replies/information/advice!
Curiously, and excitedly concerned,
Seeker
edit/ad - just thought of this - no material of any kind comes off of the bowl, there's no loose material at all. Just the sound. So even though it feels "sandy", it's not loose - just texturally closest to fine sand in spots.