w-what is all t-this!?
Calm down! Let us begin.
First of all, those are the most winning talents of all time. The itens, are to be changed acording to matchup.
I almost all times start with Life Rip, Kill to Heal and transition to Caut against healing teams or Life Rip players. To Haven against high-damage teams or heroes that can only damage with shots, like Lian, Sha Lin, Strix, Viktor. Deft hands with Wrecker is devastating against tanks/shield based supports. Resilience should be pick against strong cc teams, or Pip/Moji, trust me, it changes ALOT to have that against they in a pick off.
If any of the situations i've said before do not honor, nimble is the way to go. But the talents theyselfs give tons of movespeed, and nimble will mostly help to engage. Remember to long-range tap people that are dying to get the procs, it can change some results as everything will proc and you may get out alive or win a 1v1

Now, in dept:
Q: Why Kill to heal and Life Rip? In the way i enjoy playing, i almost never get healed by healers, unless i'm at low life and run towards they. Its usually very strong early game when caut are still small and it can change to a sucessful pick off and escape to getting outplayed and failing to remove someone from the battle. This scales even more with the lvl. 4 Victory Rush;
Q: Haven on a flank? Are you mad? As for the same reason, the damage reduction can get preety cheese and help you out on situations you could get insta killed, like taking a strix/sha lin headshot. It may look small, but combined with dodges and skills, it can ensure that you will last way longer to be a nuisance. Remember, dealing damage is important, but dead people can't do damage.
Q: Why does Deft Hands and Wrecker kill tanks again? Soo, the thing is, you can out-source a tank damage if you move pattern is on the point. It works on your poison too, making it even more deadly.
You don't have to get both, but they are in the same section for the same reason. Sometimes, you will need to get both, such as Inara matchups. Deft Hands is preety much a garantee that you will not get out of bullets, helped by Decrepify.
Q: Cauterize is the meta, i brainlessly build cauterize first! Right-o, heres the thing. Cauterize is good but for a first item, its most-likely already stacked out in your team. Trust me, if you do it right, no way you're going to need it in the early game. Its still very useful against healers and lifestealer. But its even better to buy it when healers start to get itens.
Q: R e s i l i e n ce B o y s Its good against CC, prevents you to get chained and not be able to vanish out in a escape. Also preety nice in some scenarios like 'wombo combo' teams that require stuns. Its a must against hard-to-pickout champs like pip and moji.

Q: Nimble botton tier? Whats this? Most of the builds point nimble as the best! Step on the gas!
Is Nimble good? Yes. Does it help that much in skye? Not quite. Why? the thing is, when using the Victory Rush you are already fast, nimble is great for dodging and engaging, but a bit 'too much' on escaping. Sometimes, you can flank and multi-kill their whole team, making this a bit irrelevant;

This is a alternative build if you're not skilled your team really lacks frontline and healers. It changes a bit of the dynamic of how you play it. Its most based out of counter engages and playing near your team; It can also be used with another flank to destroy their backline and still have sustain.

Q: Hourglass (Chronos) at skye? L m a o. Yup, just like healers, having cooldowns ready is great for those clutch healings. It can really change the direction of a fight.
Q: The chains again... Resilience can save you up, and it helps alot to get back at a safe zone where you can heal faster. Also great to avoid geting chain-cc and one-shoted.
Q:Haven. I've read the first build and understood why i need it. But why here? Mostly cause later on cauts will rekt you and its better be safe then sorry! In dept in the first build.
Q: Haste up! Put on your red shoes and dance. Yes, nimble in this build is great. We don't have as much of mobility since it lacks ninja, and a high level victory rush. It can help you stick in with your team and also have the flexibility to flank when you can.
Q: Caut last? As i said previously caut is usually already stacked-out in your team. If not. Get it.

https://www.youtube.com/watch?v=58wwMzkEoTQ
This is a very hard build. It is ment to kill people and more people. And even more people!
It lacks damage, but once you chain kills, they wont stop. however missing poision bolts can cost your life. Tread with caution.

Q: Caut first! yay!! Yup! Caut first! Let us make sure if theres no mercy. Caut will prevent heals and be very harsh against some matchups.
Q: I've not met one who can outsmart bullet. If theres no need for caut, deft hands is your choice. The ammo management goes really nicely and you will amost never lack the damage from your mouse1.
Q: Life Rip again? Very useful, still good at some early 1v1's against healers and such.
Q: Morale boost? Wee! First of all, its not polite to stare at a woman's bombs, second, more bombs, more impact. More teamplays, more kills, and killing is the point.
Q: Shields? Damage! If killing is the focus, we should not be stopped by shields, amirite?