On another note, I wonder whether the 30% may be more based on available flake size which meets those specs without too much milling or being smaller. The other flake sizes could be better suited for other applications? Would appreciate feedback on this question please.

That is an interesting take on where the 30% is derived from. On my first read of the release, I assummed they were just talking in generalities saying something like "Our whole target market is $10 B per year and batteries make up 30% of that". Just a percentage of possible target markets.

But someone else (was it LT Gold) thought it might be based on 'interest to date' so to speak - what volumes certain end users are looking for.

Your take is different again, I don't think there is any way to prove or dis-prove your theory but it is an interesting one for sure.