9x +0.87 magic penetration
Greater Mark of Magic Penetration
9x +1.19 ability power
Greater Glyph of Ability Power
9x +1 armor
Greater Seal of Armor
3x +4.95 ability power

Seals: Flat Armor Will keep you alive vs most AD matchups. Even hybrid matchups do a lot of damage from autos in early game.

Glyphs: Ability Power
Roughly 11 AP gives 3.3 dps to poison at level 1 (15% increase at level 1)
Helps you proxy 3 waves easily
Helps you out-trade your opponent pre-6 (your weakest phase).
Helps your Deathfire Touch reach 5 dps at level 1

Marks: Magic Penetration
Gives you 3 more magic penetration than hybrid pen marks.
I've decided to switch to these because throughout the course of a typical game,damage is about 94.6% magic and 3.8% physical (from auto attacks)
This scales better into late game than hybrid pen marks.benefits more from this because my most recent build on him is more damage-oriented, so he gets more AP sooner and the buff to his fling (6-8% max HP target damage) means he will hurt more and benefit more from these marks.
Additionally, changes to minions in season 5 removed armor so armor pen is no longer useful for last hitting either.

Gives 15AP which is 4.5 dps on your poison (20% damage increase)
Together with glyphs, makes your poison about 35% stronger at level 1.
Helps you easily proxy 3 waves at level 1 before going to lane
Helps get your Deathfire Touch to 5 damage per second at level 1.

Well they key for this meta singed is he got 25% summoner spells reduced cooldown by geting insight mastery and Ionian boots of Lucidity , ghost has 135s cd and ignite 155s so singed becoming assassin,wich is pretty good when you have to carry games or snowballing in lane with a huge advantage,good luck with the assassing singed,have fun.