Hey guys, just read a really thought provoking thread on HB, and whilst not going to take as absolute, will definitely keep it in mind. It's mainly Jim Schulman's responses that are fascinating...

In a nutshell, with coffees with a higher bean density/brittleness it would be better to grind coarser which produces less fines (which blocks up espresso shots and can cause channelling etc), and softer beans a finer grind/higher dose due to less fines present in softer beans. Grinding finer to produce enough fines so the shot doesn't gush towards the end.

All new stuff to hear for me anyways!