I found time to play around with adjusting the OPV on a Gaggia Classic using my Silvano as a benchmark. A perfect method? probably not. Pretty close? Taste does not lie - same beans, dose, and grind produced similar tastes and near identical flow patterns. I think the Classic is dialed now.
Here is what some Velton's Bonsai Blend looks like (ignore the dirty glass - it was working overtime this afternoon):
A little tight using my LaPavoni PBC sample grinder:
Loosened up a bit - was Guinness while pulling - by the time I got my camera out again it had settled a bit:
It ran blond at the very end - look at that blight on an otherwise perfectly flecked crema top:
