With the La Pavoni I don't always feel the resistance on the lever when I would like to, especially when I turn the heat to low which results in less preinfusion pressure, so I will push a little of the water down into the puck and pull up again to fill the brew chamber with more water and push down again this prevents me from getting tiny shots that would be less than 1 oz.
I have an older model Europiccola that will kick into charcoal mode (overheated water burning the coffee) if I don't carefully manage the temperature.
My family member likes very very milky lattes with only a hint of coffee flavor so I only put about 2 teaspoons of espresso in their 8 oz latte. The milky lattes are not devoid of coffee flavor in fact in reality it has a profound effect on the milk flavor. Let's just say my family member does not like espresso flavor to be the dominant one in the drink. This leaves me a good amount of espresso to play with.
I was once shown a real old La Pavoni (older than mine) which had a wider group head, or maybe a different shaped one, but the same sized (49mm) portafilter, in a repair shop. I asked about it and was told the very old ones have a sleeve in them. He also told me that it was an advantage over newer ones (newer pre-millenium.) I am not talking about the synthetic sleeve in the millenium models. Does your have that sleeve ? and how does it affect the brew.