There are some easily explained changes here, and some more challenging ones. The main counterweight stub mode at 800 Hz is clearly gone, and its 1600 and 2400 Hz 2nd and 3rd harmonics are much lower.
The bearings resonances are lower as this particular prototype uses a better tighter bearing. It's amazing what difference better tolerance balls make.
This leaves us with 2 unexplained artifacts. First, the much higher headshell resonance. I've used a different Picomin 22
this time, and it might be that its behaviour close to its own 11 kHz resonance is different. But I suspect it's not the only reason.
And second is the main armtube mode. It's a bit more pronounced, and this change can't be explained away by different calibration or measurement error. It looks like increasing the rigidity of whole tonearm has a side effect of making main armtube resonance more pronounced.