Need help to improve my very good SRS Poison Necro (35mio dps atm)

Hello Pro's
me (Casual Player) needs help by all who knows the math behind. Followed basically two guides (Maxroll and GhastyTV/Balormage) but read at least 4 or 5 others and played a lot around the tree and gear myself.

Now my Build is really good but I'am hitting my 'Knowledge Wall' now.
Can you pls check my Build and help me to see if I made obviously mistakes and where is room to improve. I stated all my open questions in the notes section of the POB.

Thx a lot
ogli

https://pobb.in/JA54zp95rd0b

P.S: Minor issue: if someone can check if I set up POB correct, this would be nice, too. First time I did it.