Have done Scottish descent kilted funerals in Clergy Tartan, but only if Kilts are being worn by family members (with or without a Piper).
Also for weddings of the same type. Otherwise I wear my usual Vestments for such occasions.
I think Clergy Tartan would be the most appropriate Tartan for Ordained Clergy, but of course most folk wouldn't have a clue, nor be related to the "Kilt Police", so one can wear whatever one prefers, I guess.
But I confess to feeling a bit 'put out' when I see the unordained laity (licensed by the state) doing weddings in Clerical Garb or Clergy Tartan-when they are not Clergy. But that's just me. I know when to keep quiet.