A few printouts made it clear that spring loaded chopsticks would be more ideal than hooking catch points.  It's just really fiddly to get the catch points to engage & disengage without making a mess of the ashes.

It wouldn't be possible to completely open spring loaded chopsticks though.  It wouldn't be as visually appealing with big old springs on each side.

Accepting the problems for now, the 1st burn looked really like it just landed in real life, with the engines smoking & the whole rocket hanging from the chopsticks. 

Ash removal was a complete mess, as expected.  More tweeking of the catching  points got it at least possible to empty the ashes with a lot of care.

Didn't take long to notice the ship sitting lower after every landing burn.  The walls were melting.

CA glue can buy it time, but CA doesn't stick to PETG permanently.  Thicker walls & more layers for it to pack down would be the next step.  Definitely not getting narrower than 50mm.