Support cleric is:
full mag build,
vit tome / mag tome, dragon cape / supreme robe, purify weapon / dragon glavie - switching depending on situation
dragon neck, WS belt, ancient dragon robe, r8 legs, shoes and wrists
When it comes to r8 stats you'd want as much -channel as possible.
If you'd like to deal some damage, you will additionally need atk lvl glavie, r8 top and DS neck and very good knowledge of cleric combos.