Youtube views : safe ratio?

Hello,

I own a music band channel for a few years with around 1500 subscribers and approx 300 000 views (mainly legit)

I would like to buy some high retention views to help ranking for our upcoming music video, but I would to minimize the risks as much as I can. I don't want our 8000$ videoclip to be removed by Youtube

QUESTION : what is the % of fake high retention views a video can safely have ? 20% ? 40% ? more ?

Thanks in advance!

it is changed, do as little as you can to be more safe
also in many cases I do huge amount of views with no problems from youtube

Okay thanks!