MediumRoastSteam The reason I was using 17g was simply because I was finding it very difficult to get more than that in the double basket that came with the Minima, at 18g a lot spilled out, because normally, as you suggest, I’d be trying lots of different weights.
I finally, with a lot of care, and still some spillage, managed to get closer to 18g into the basket, but had to make the grind yet courser, to 26.5 to get a better time for the shot. That gave me my 36g out at close to 40 seconds.
This morning, without changing grind settings I bought some French Roast, still quite a dark oily bean but less so that the Santos Double Roast. Still difficult to get 18g in the basket without spillage but this time I got my 36g out at around 35 seconds and it was very tasty. The puck was drier too - so things are heading in the right direction; just slightly strange that the Niche at 26.5 is a little outside the espresso range according to their dial, but @hornbyben mentioned that at first it’s normal for the grind setting to be higher until things have bedded in.