Gaggia filter basket size?

[A.Nunez]

I bought my 1st espresso machine recently which is a Gaggia Baby Twin. I'm new to espresso brewing. I've been watching multiple videos to learn the basics. I think I have I t down for the most part. I had a question about the Gaggia double basket. Everywhere I read says the Gaggia basket should hold 14-16g of coffee? I've seen a lot of videos where the barista fills the basket and levels off the grounds then tamps without measuring. One video measured and explained the basket should range from 16-18g of coffee. So any thoughts about average amount of grams per double shot basket or Gaggia basket to be specific?

 

[Coffeefix]

Most websites quote around 7g of coffee per shot if making Italian style espresso. This would usually be a blend of beans.
Modern "Barista" style coffee bars here in the UK are often using a lot more than 7g, sometimes double per shot of espresso and they are often using single variety Arabica beans. Not my idea of a good espresso but each to their own...
Domestic Gaggia machines use the same filters as the commercial Gaggia machines so it should be easy for you to source other sizes.