General

Just a btw guys. My self buffed range is 26.5k and I can easily solo Zak in ~14m as long as I'm using my hyper as often as possible.

I guess you'd need 50k if you wanted to do zak in ~5m.

EDIT: Should mention I have 30% boss on top of attack buff

50k for all but CHT, as I am not sure what range you would need for that one.

And if you mean the regular Root abyss bosses by chance, I can solo Pierre, Crimson Queen and Von Bon very quickly. However, it takes me almost all of the time given to defeat Vellum. (My range is about 95k transformed)

Assuming that you maxed out gigas, maybe 50k for all?
Except chaos root, the second I read that *facepalm*.