Tartan Day Kilts

Only if you are marching with a society or attending something formal. Spectators wear whatever they like, and a tartan scarf or tie is more than enough to take part. Clan society marchers generally wear full Highland dress.

Your clan sett if you have one, since Tartan Day is specifically about heritage. If your society marches under one sett, wear that. A district or universal tartan is entirely correct where no clan connection applies.

Yes, and it should. Send a roster with each member's waist, hip and length, plus the sett required. Ordering together means one weaving run, so the group matches in photographs rather than showing batch variation between individual orders.

As early as the roster allows, since group orders are cut and finished together rather than individually. Collect measurements first and place the order as one, rather than letting members order separately as they decide.

As soon as the roster is settled, since group orders are cut and finished together rather than individually. Collect all measurements first and order once, rather than letting members order as they decide.

Yes, and many societies do exactly that so the group reads as one body in a parade. Send us the sett name and the roster, and every kilt is cut from the same weaving run.