I like the 5-gram suggestion. As a new Bianca owner, it's hard to even know where to begin experimenting. Being able to test different preinfusion times would be a great place to start, and the 5-gram benchmark enables just that.
But I wonder if this approach is a bit too scientific.
Some pursuits are more like art than science. Take baking and stove-top cooking. Baking is chemistry; it requires the careful combination of materials in just the right way to get the reaction you want. Stove-top cooking is more spontaneous; great cooks make on-the-fly changes using a tool-belt of techniques. Both cooking and baking are, at bottom, science. But artisans in each field approach their craft very differently.
For a long time, making espresso with a non-lever machine was like baking: Get the best raw materials, pop them in a portafilter, and hope for the best. Now, machines like Bianca and the DE1+ let us change our technique from shot-to-shot, almost on the fly. Now we get to be like chefs.
Shouldn't we focus on developing techniques, rather than quantitative benchmarks? For example:
Lever style shot
Wouldn't it be great to have a language of different techniques, and corresponding knowledge of how those techniques affect the shot. What are the techniques that make great espresso? And how do those techniques apply across different roasts, beans, and temperatures?
*edited to change seconds to grams.