otherwise they will be prone to warp and collapse in on each other. If your item will be as tall as you suggest, this is likely to happen before the print even finishes

Yeah, this is what happened in the original, failed print.

I ended up making the model with 3mm thick walls, using two perimeters and 10% adaptive cubic infill (I sliced with gyroid as well, but it looked weird). Turned out great. I made some that were not quite as tall as well, with 2mm thick walls and 3 perimeters, which worked fine as well. It might have worked for the main boss here as well, but I’m not quite sure. The difference between the models was about 55 mm in height. The difference in material usage between the two options was negligible (< 10 g), with the infill variant coming out slightly lower in consumption.