Jonathan's Necro Supports: Necro Healer SPC/PA - Necromancer Construye PvE - ESO

So for stats with Bewitched Sugar Skulls on (the best food since it is great and it is cheap) you should aim for 22k magicka, 37k health, and 25k stamina. 1k over or under for any stats is fine! If you are a bit nervous about surviving anything then aim for 40k health and evenly reduce your magicka/stam. 

Your major resolve source can be Beckoning Armor or Balance if you have mages guild leveled. Inner rage can be swapped out for Destructive Clench from the destro staff line for a ranged taunt if targets aren't too far away. Revealing Flair from Alliance War can be slotted on your front bar instead of Slurp if you are in a high damage situation where you are struggling. Just slotting it gives 10% reduced damage.

Tanking is more of an art than a science. Some changes you may like are swapping your mundus from Atronach to Steed. You may make one of your jewelry traits Swift for movement speed. You can swap one of your blue slottables for  Bulwark which gives 1900 resists. 

Some defensive options when you are struggling with survival are slotting Revealing Flair, replacing Turning Tide on both bars for Drake's Rush frost staff and master sword and board (from vDSA), replace your monster set with Engine Guardian, and replace Aggressive Horn with Ravenous Goliath if you really need to live.