Solo: 11,225 now → 15,320 by point 100 (+36%), with your own Attack aura on and no party auras or party vulnerable. Hunter's Mark is worth much more solo (+16%) because it replaces the party's vulnerable, though mana runs short solo and Hunter's Mark IV adds nothing on its own, and Parasitic Arrow IV costs slightly more mana than it returns (15,370 at point 95, 15,320 at point 100).
Party settings: four party auras (Attack, Haste, Defense, Wisdom) and 16% party vulnerable on the target. Planner estimate using your real mana regen (81.9/10s with Party Wisdom), cooldown reduction and the 95% hit cap, run at Mastery 100. Stats will shift as you level, so treat the order as a guide.
Ability slots: the final build learns five abilities (Hunter's Mark, Arrow Shower, Parasitic Arrow, Piercing Shot, Rapid Fire) but you only have four slots. The planner's best four are Hunter's Mark, Parasitic Arrow, Piercing Shot and Rapid Fire, so Arrow Shower gets benched. You still need Arrow Shower I to III because Single Arrow and Apex Predator hang off them.
Tier IV nodes (Rapid Fire IV, Hunter's Mark IV, Parasitic IV) need Mastery 60, so save points from 60 for them.