skylark 38g plus 190g is 228g, so a 1:13 ratio relative to the dose weight. In normal filter strength range, but espresso contains a lot more non-dissolved solids than typical filter coffee and as the drink gets more diluted these can make the cup taste flatter, duller & drier. So I tend to prefer a higher concentration, add the water little by little, stirring in between until it is just weak enough to enjoy.
Once the shot is pulled, extraction is done - you have what you have in the cup, the flavour balance is set (bearing in mind the above), you are essentially just making the drink more diluted. You really need to check the shot before dilution to troubleshoot any extraction malfunctions.