Update : I ended up using "F22 ACCY 5A" as switched - F22 was not listed in my .pdf manual (just shows a "-"), but it was moulded into the back of the plastic instrument panel fuse block cover.
...and then used "F11 AMP 25A" as constant. I have an LT, so I don't have the Bose Subwoofer Amplifier.
NEG/BLK - There is a downward facing PEM stud to mount a tray to the right of the instrument panel fuse block.
I used this chassis point as NEG/BLK (reversed 10mm nut a little, inserted spade, tightened).
System works as expected.
Each circuit is using a 5A fuse inserted into the panel like any other active circuit in the panel (OK - aside from relays and breakers...

).
I could not find anything smaller i.e.: (2A / unicorn?) in Micro2 type. 87% sure that 5A is smallest available.
The original "provisional F22 ACCY" calls out a 5A fused circuit, and the "provisional F11 AMP" is a 25A fused circuit. Both wire sets are protected with something "equal" or "smaller" now.
The camera itself w/Hard Wire Kit draws 1A maximum at full go - everything on / Front and Rear camera, GPS and Wi-Fi Cloud connected.
The Park Mode DIP switches are set to turn system off at <12.5VDC threshold or 24hr duration - whichever happens first.
I test wired the system (twists and clamps) and drove around with it for a few days first - to ensure no nuisance trips - checked that as good, then hard wired it.
Perhaps I should not comment on Premier versions, but tapping piggyback into the F11 25A subwoofer constant seems like a safe way to hard wire a camera park mode device.
The amp (F11 at 25A slot) will have monster draws with headroom (off audio transients) compared to a dash camera system, and should not interfere with other functional / safety circuits.