Level 91 Raise Zombie Necromancer^3.22

Notes

Crafting Convoking wand (min ilvl 60)
Spam Harvest speed reforge until you get +1 minions and an open suffix for trigger craft.

Alternatively
Alt + Augment spam until you get +1 and speed, can also try to regal if you get +1 and a random suffix.
Finish with Trigger bench craft

You can also try bound fossils, but they can be pricey early in a league at least for me they're very annoying to try and farm.
These shouldn't also be that expensive to buy off of trade, +1 with a small attack speed roll isn't worth a whole bunch.
If you're having trouble getting a +1 roll, a 50% minion damage roll is roughly equal to it early on in DPS, but it doesn't help minions stay alive and it scales worse.

Crafting Shield (min ilvl can be anything, really. Just the highest you can get)
Spam Harvest crit reforge as minion crit is the only crit mod on the item so you're guaranteed it. 
Then just get a decent enough of a minion damage roll preferrably a spell block roll although you can probably skip it early on and just get a better shield later.
Finish with bench craft

Crafting large cluster (min ilvl 75)
Spam Harvest crit reforge. Vicious Bite is the only crit mod on the jewel so it's guaranteed.

Crafting medium cluster (min ilvl 68)
Spam Harvest life, speed or chaos reforges. The chances of landing on Blessed Rebirth aren't amazing, but it's also not all that hard to get.

Alternatively
Alt + Augment spam until you get Blessed Rebirth
This cluster might not be necessary because we're investing quite a bit into minion defenses with Grave Intentions and Indomitable Army etc.
I'm not sure Skeletons will live enough with those, but if they do you can just skip the medium cluster entirely.

Crafting Abyss Jewel (min ilvl 35, preferrably 74+ for higher life rolls)
Alt + Augment spam or Harvest reforge life

Spectres
Use Carnage and Host Chieftain monkeys for charges, add in Demon Harpy, Pale Seraphim or Arena Master for your third and fourth.


On the topic of the tree, the crit nodes gain a lot of value if you get a Maata's scepter early on so you should probably rush to those 
Swap Vulnerabilty to Assassin's Mark when you get Maata's

Flesh offering is going to be better very early on compared to Spirit Offering so PoB every now and then to see when it's worth swapping over. 
Or just wait until Maata's and swap then