Many people have different methods of sorcing, I think mine is unorthodox so I won't confuse you with my specific advice. Some things to consider though:

-Julianos uses 2 slots to give you 6% crit chance, which isn't a huge amount of crit chance, and crit chance doesn't go very far in cyro.
-Kagrenac's Hope gives you 75 spell damage less than julianos but also gives you magicka regen and max health (which is more useful than 6% crit imo).
-Dual Wielding prevents you from weaving basic attacks in with your skills. It also leaves lots of space between skills giving your opponent plently of time to read your animations and respond to your attacks.
-Lightening staff heavy attacks can't be reflected, but also can't be weaved.
-Fire staff heavy attacks can be weaved with your skills to increase the pressure on your opponent. Pressuring your opponent is important in fights.
-As curse, frags and mines will probably be your hardest hitting regular skills you'd be better off putting most of your cp into thaumaturge and then some into elemental expert to boost streak, wrath and overload. I have 76cp in thaumaturge for 20% damage boost to curse/frags etc. And 26cp in elemental expert for around 10% more elemental damage.
-Hardy, Elemental Defender and Thick Skinned affect the damage your ward takes from magic/elemental damage and dots so invest equally into these.
-To answer your last question; the priority for a pvp sorc is probably spell damage but you also don't want to neglect regen or max magicka.
-36k magicka and 77cp in Bastion should be enough to get your Hardened Ward value over 10k, which is enough because it can be spammed.
-People have differing theories on regen, some think 900 magicka regen is fine (although I don't know how). In reality I have 47cp in Magician and a spell cost reduction glyph and I find that even with 1700 regen with regular weaving I still run out of magicka occasionally, not often though.

Not sure what you are like at acquiring gear but a good gear combo is 5 kagrenac's hope, 3 arch-mage, 3 will power.

CPs look good. The only thing I would say was with only 329 you might want to avoid putting 100 in anything. The returns after a certain point are so minimal. For example 77cp in Bastion gives 20% boost to wards, whereas 100Cp in bastion only gives 25% boost. Those extra 23 cp could be used elsewhere in that tree, like in Hardy , Elemental Defender and Thick skinned.

Also I think you have too many cp in elfborn for a pvp build with the number of cp that you have, that's just my opinion though. I have 5 cp in elfborn lol.

Also with only 16cp in magician I would recommend a cost reduction glyph if you don't already. You need some cost reduction imo. I also put points into befoul to aid the disease glyph on the staff. Not sure how much of an advantage this is but I only have 9cp in befoul, need to do some more testing there.

Aside from that cp distribution looks good. I love how everyone has 1cp in spell erosion lol