IPv6 Proxes Per Youtube Account

Hi All,

I have over 20000 IPv6 IP addresses each in their own /64 subnet.
At the moment I am running 1 Youtube Account per /64 subnet on a fixed IP.

I would like to explore adding more accounts to each /64...

My questions are:
1) Is there any reason why I shouldn't do it?
2) Should I have multiple accounts on the same IP in the /64 or create more IPs in the /64?

Thanks in advance!