DW Knights - Mace or Sword?

Very fortunate to get my hands on the Christmas battleforce and struggling to decide which weapons to put on my 2 DW knight squads. Tempted to have one of each, but unsure if maces work best when lead by a Terminator Chaplain? Or what leader best to attach to the squad, and run as a 5 or 10?

So many questions for my small brain