if you look on wiki at spells, it lists what slots buffs go into
http://wiki.project1999.com/Valor
http://wiki.project1999.com/Armor_of_Protection
valor and armor of protection both go in slots 1, 2, and 3
http://wiki.project1999.com/Spirit_Armor
spirit armor goes in slot four
so it stacks with spirit armor, but not valor. looks to be good as a self buff thats slightly stronger but with basically twice the duration