Sizing of return air and supply air linear grilles

I'm installing a Daikin VRV system, 4 low static ducted hide away units and 3 floor mounted, vertical discharge units.

My question is how do I size the return air grille and the supply air grille. The client has requested the linear type.

I understand I need to start with the airflow of the particular unit on high speed but from there I have no idea how to proceed. Fortunately there is only on supply grille per unit.

Any assistance will be greatly appreciated.

PS. If I could have the examples in metric it would be greatly appreciated.

Airflow and throw decide the sizing.

Try this catalogue to get you started.....


https://www.google.co.uk/url?sa=t&so...03_hJl0L4kT37w

Thank you.