Coarse sand is made of bigger particulates than compared to play sand which gives it better water drainage. So yes it is superior to play sand.

As to where you can find it hopefully someone else can give you an idea

1/10 to 1/8 of an inch, minimum.

Josh

Hi Josh, many thanks. But for example - I'm not sure I understand who is going to know the grain size of the sand and/or how do I determine that?

Particle Size Chart from UC Container Soil Mixes Book. larger sizes particles >1mm to below gravel are termed Very Coarse Sand to Grit.

Grain Size Chart

Often sand is graded by screen size.