General
This build uses 2 active damage shields and 2 block activated damage shields to stack full health damage shields at once thanks to the way warding contingency activates. The damage combo I prefer is based on the traditional 4 skill combo for magsorc that uses Haunting Curse, Endless fury, Elemental weapon (spammable of choice), and Crystal Fragments. We use Nightflame monster set to supplement healing overtime and use Vibrant Shroud for burst heal and to buff healing and shield strength. Fully buffed with Death Dealers Fete we reach up to 32k health with at least 30k damage shields, 52k+ max magicka and 4k spell damage with 33% crit. While the build may not have the highest stats, it is very effective and balanced allowing for very effective damage shields and healing with excellent burst and mobility. Resource sustain is easy to manage as well.
Skills
While I prefer the old school damage setup this works just as good with the more common 3 skill burst rotation (curse, spam, frag) and is very interchangeable with whatever skill choices desired. I sometimes get rid of endless fury for a 3rd activated damage shield. You can stack a great deal more max magicka by slotting inner light and/or other mages guild skills front bar making your damage, healing and damage shields bigger. However, most builds do that. This setup is specifically made to make the old school magsorc gameplay feel viable in today's meta. While having a 3rd damage shield seems like it should be stronger, it doesn't necessarily feel that way. Using the 2 (+the block shields from psijic passive and reinforced Warfare cp slot) feels like more than enough and makes it easier to spam vibrant shroud for burst heals as needed. Shroud buffs healing and damage shields while also reducing damage of enemies so it's a very strong skill for this build.
Gear
I went with Crafty Alfiq front and Three queens on back to stack the most max magicka I could while also having room for Death Dealers Fete and Nightflame monster set which is what makes not using crit surge viable and boosts stats, healing, damage and shields viable for me. Alternatively Engine guardian would be a solid option for this build, but I liked Nightflame because of the stack of max magicka. for backbar set lich or wretched vitality would be good but I think for this specific setup Three queens works quite well. Until I got Death Dealers I had 4 pieces of 3 queens on front which felt quite strong. Also I use the heavy trainee chest with 2 heavy for the monster. I would use a medium shoulder if I had it to get 2% more max stat from undaunted passive.
Champion
Pretty typical magsorc choices here. The notable difference is that I use reinforced instead of Duelist Rebuff to get the full health damage shield. After testing I might drop it for the rebuff.