It really depends on which super rare ninja you like. As for me, I really like Kurama Naruto that's why I'm focusing on GNW Treasure and hope I will get him but if I get Madara, it's still fine. I'll just save up again and pull again until I get Kurama Naruto.

I would say GNW. They offer you two great SR and a bunch of really good rares.

Someone also suggested some time ago to spend into Kage until the first rare, then move to GNW.

Honestly with your lightning main i would suggest to get lightning treasure which you need 210 seal scrolls, with rares being pulled at every 60 scrolls you can make it decent line up with 3rd raikage Ay,Samui and Omoi ,that raikage is the super rare,Samui is lightning variant of iruka with shield/stat boost/interuption mystery and Omoi gives shields to any Kumo ninjas with his mystery also he summons 2 slones and has passive to dodge any mystery once per round,oh and if you got any of rares then that means you are closer to super rare

to find out if you are close to super rare ,you can count your rares which as i said are 60 seal scrolls,Kage and GNW super rares are 900-1000 scrolls

good luck bro

If you want a cheap useful super rare you can go to Cloud Ninja treasure with 3rd Ay, it'll be useful for early game

But in later period I'd rather focus on GNW treasure getting Kurama/Madara, Kage treasure super rares are really outdated (however the rares with auto-barriers are still great)

Ay 4th team works perfectly fine even now if ay is enough stacked.