I am trying to dial in my GS3 with a new espresso and I am trying to makes sense of the dial in parameters.

I am starting with:
Dose: 17grams
Temp: 198
Extraction time:23 sec.
Shot volume: ????

I have trouble understanding shot volume. Is that with crema right after shot or after it settles for a few seconds I notice the volume can drop by as much as .5 oz. So if I use the top parameters I will have 2.25 oz when the machine stops but only 1.25 oz of espresso after it settles for about 30 seconds.

Also the volume will be different if I use the naked portafilter vs the double spout (naked produces more crema). Advice please...

Take a look at this: Digital espresso or a way to consistency

I hope you are using 17 grams and not 17 oz For 17 grams you are looking at 22-28grams of espresso depending on coffee, but let your taste be the guide.

prcoulson wrote:Advice please...

From the FAQs and Favorites, see Espresso volume includes crema? I prefer brew ratios for comparing notes since it's based on weight, not volume. From what you describe, the coffee may be "too" fresh, which produces an almost effervescent crema that collapses quickly and has off notes of baking soda.