Nep v2 share mechanics

Share mechanics:

Base shares at the start of the game:
5% Planeptune, 29% Lastation, 10% Lowee, 15% Leanbox

Increases/Decreases:
+5% per quest
+15% per PR level
-0.2% per hit on your CPU/Candidate that does non-zero damage
-1% per manual HDD activation
-20% per CPU/Candidate death
(these are already counting in Zero Arc, so Planeptune has 0% at Hyper title in NG runs)

Amounts needed:
30% to qualify for TOP status (as well as having the most shares)
40% to see Lastation/Lowee/Leanbox dreams
60% to see Planeptune dream

What to abuse this knowledge on:
Lastation can and should be abused heavily on both NG with DLC and NG+ (True End only obviously) - switch Noire out of the Gold Third battle and keep all 29% shares to speed up her story significantly by skipping all chests and allowing you to buy Forbidden Twigs in NG+.
The others probably aren't worth it - except maybe Lowee on NG with DLC, though that one's on a knife edge and Blanc will probably take a nonzero hit even with DLC armor.

UPDATE November 2016: Since the time of writing, a method has been found to abuse Lastation's starting shares in NG runs even without DLC. The method depends on getting out of the Gold Third fight with the maximum Lastation shares possible (8.8% after one hit + one death) and then playing carefully/getting lucky enough to still have 5% after the Exhausted Jelly quest is done so that the dream can be triggered with only Level 3 PR. Look up Dabomstew's 12:29 IL of Noire's story True Ending on speedrun.com (or any run that beats it, probably) to see this strategy in action.