Definitely jinchuriki 1 and try to get roshi. Freeze your level at 65 coz more and more whales are freezing their level now, too..
I've seen someone with 50k+ power at level 70 and he just refuses to level up, maybe for "another 6 months" or more.
At level 65, you pretty much dominate sage just by using a root of warrior lightning main, skillbroken kurenai, skillbroken sasuke and iruka.
Sasuke - Kurenai - Lightning Main
X - Iruka -X

X - X - X

Talent: 2 - 2 - 1 - 3 - 3
Summon: White Snake
Build your initiative so your main will always cast mystery off. I've used that lineup for so long and can even defeat people 2-3k power above you.
When you feel confident enough to advance, you can go on and STOP at level 70. Once you get there, just hope you get Fuguki for yet another sage * with him + roshi and water main + kurenai sb.

True. So the OP should either: try to get roshi and freeze at 65, or unlock GNW treasure and save. Just hope he saves enough seals to complete the hidden mist team which is quite good in sage and arena.