So, here are the print results:
The one on the left represents the version 1 design style, which I’ll refer to as “skeletal”. The one on the right is just a thin skin of a single 0.8mm wall and two 0.2mm added layers, which I’ll refer to as “epidermis”–because it has a thin skin on it. Even just that thin veneer radically improves the appearance, and, in answer to @Bullock’s question, it feels far more sturdy and karate-chop proof than the purely skeletal one on the left, as you would perhaps expect from even educated guess alone.
Looks as though I need to recalibrate the non-initial layer flow rate to fit this particular PETG filament, and then it will look even better, and be even stronger, regardless of whether skeletal or epidermis. It was originally tuned for a grey filament, same brand, but I guess either the white color or other batch differences or perhaps even change in formulation caused some drift in flow rate away from the original calibration on grey.