General

Range to Zak

So I'm pretty sure I'm nowhere near the required range to solo zak, but I'd like to have a range goal to reach in order to solo...

I'm currently at ~12.6k range lvl 136 with
10 DI
10 Beholden
10 Hex
10 Zerk
1 Rush
Saved the rest of my SP

Failed 2 Zerk 20 books already -_- and I can't really afford another right now

So what range should I aim for to solo zak with 10 DI and 20 Zerk? (If I can get that damn book)

Thanks ^^