I personally when going for power on another account I only picked up 1 event ninja which was Sailor Sakura. She is a solid ninja, not OP or anything but worked really well for lower levels. Then I saved coupons for Lucky Star (Mind you I never go for the jackpot ninja) and pick up Medium Refines, Myoboku Scrolls and Charm packs last. I usually cap out on the 1st 2 and get like 3 or 4 on the Charms.

So while I spin for stars if I get a event ninja, then awesome if not awesome. That is how I got Edo Deidara and 2nd Hokage on *t.

Then when I no longer need Medium Refines (Still a ways away) I'll focus on buying Adv Refines from Treasure of the Sage at a nice discount. That or Seal Scrolls.

Meanwhile I'll stock up on about 220 Seal Scrolls then go into Jin 1, or LoL treasure as Roshi is a really solid ninja and cloud meta still works decently. My alt is level 78 with 50k power which I hit about a week ago, now I'm going for 60k before level 80 then increase by 10k til I hit 80.