This is my second print using TPU, after the calibration cube. The material is soft. The main strategy is to abandon all hope of retracting the elastic filament. Instead, to maintain a constant feedrate so the pressure in the hotend can stabilize, cross perimeters as little as possible, and do rapids as fast as possible.
any quality digital calipers that measure in both inches and millimeters will go a very long way towards reverse engineering. I'm still using an inch dial caliper from 2014.