I can't compare the chamois to PI, but I have some shorts with the she-lastic chamois and I don't think it's thin.
Based on the description, it does not sound like they are thermal. But what kind of temps do you want them for? I would think they would be fine for temps in the 40s-50s, at the very least.
- Gray 2010 carbon WSD road bike, Rivet Independence saddle
- Red hardtail 26" aluminum mountain bike, Bontrager Evoke WSD saddle
- Royal blue 2018 aluminum gravel bike, Rivet Pearl saddle
Gone but not forgotten:
- Silver 2003 aluminum road bike
- Two awesome worn out Juliana saddles