Please know that whatever he wears, Amelia is going to put her hands all over him both before and after this party because he looks so damn good all dressed up.
He may even be wearing green to match Chris. The Amell house color is red but he's been tending away from it into blue for himself or green for his relationships
Hm... double breasted green coat with a similarly double breasted lighter waistcoat with embroidered lapels. White silk cravat, cream fall-front breeches but with his everworn black riding boots.