I've got a Bambino Plus and so far the only customizations are a bottomless portafilter, a huge single wall basket (IMS), programming the flow presets for a good ratio by weight in/out, and optimizing the grind specifically for 30s duration. I'll have to look into your OPV suggestion; anything else?
Bambino might be OK stock?? Not sure. Only change the OPV if you have a problem to solve. For me it was slightly too fine gets zero extraction and the pressure compacts the puck. Then go a bit coarser and it spews out.
