Just an FYI: Ristretto shots (brew ratio greater than 1:2, aka "pulling short") are likely to be under-extracted because there's less water moving through the coffee. A finer grind can compensate somewhat by exposing more surface area and slowing the flow for more contact time but, as mentioned, after a certain degree of fineness the "fines" will pack togther and block the flow enough to decrease extraction.
Ristretto shots were commonly used by third-wave cafes back in the day when espresso blends and SOs were roasted darker than they are today. Those coffees tended to over-extract and taste bitter when pulled Normale (1:2 brew ratio.) Ristrettos usually don't work very well with today's much lighter roasts, which are harder to extract. Typically the result is a sour, under-extracted shot.
The revised shot worked for you because you pulled enough water through the puck with enough contact time to get a full extraction. These days Lungo shots (brew ratio less than 1:2, aka "pulling long") can be the solution for pulling very light roasted coffees.You might find this thread helpful