For a Saladin vigil I'd want range and stability perks, and accelerated coils if your lucky. Hip fire fusions can be good too, especially with a fast charge rate

Any roll on that gun is good...kinda a rarity in destiny...you may want to avoid accelerated coils,as it lowers the impact and this takes another bolt to kill...fusions shoot 7 "bolts" with the vigil in pvp it takes 5 to kill, with accelerated on it takes 6

Uses enhanced battery( light weight does almost nothing) and play around with the range and stability perks ( hard to judge a fusion rifle) but in my experience stability is a more important stat then range on a fusion, not saying range on a fusion of bad tho.