In simple terms blonding determines the shot, in more detail I pay attention to the flow rate, blonding, viscosity and 'feel'.
Good words. That helps me firm up in my own mind what I've been trying to do w/o realizing it. My machine being where it is, has poor lighting at the PF. So I have a hard time making fine distinctions when it goes blonde, which has me starting to look at viscosity and flow. I've actually toyed with the idea of mounting a small LED or two, maybe the head from a small flashlight on either side of the group, as long as I could do it in a clean fashion and they wouldn't blind me as I'm watching the bottom of the naked.
After reading that page you linked to, I have some other ideas. My machine has volumetric dosing, and I have it set to 2oz. on one of the buttons, but I programmed it by volume, which is hard to measure with the crema and all. Now I'm going to reset it, as a shot pulls into an empty glass tared out on scale.
Thanks buddy.