Yes, thats what I am wondering about, what rules would need to be entered.
This is the safequid rule, maybe it could be adapted somehow?
<profile><enabled>true</enabled>
<profile_tracing>true</profile_tracing>
<host>youtube.com</host>
<portrange></portrange>
<urlcommand></urlcommand>
<requestheader></requestheader>
<responseheader></responseheader>
<month active="false"></month>
<day active="false">1,31</day>
<weekday active="false"></weekday>
<hour active="false">0,23</hour>
<minute active="false">0,59</minute>
<matchmode>absolutetime</matchmode>
<addprofiles>UNSAFE_YOUTUBE</addprofiles></profile>
<profile><enabled>true</enabled>
<profile_tracing>true</profile_tracing>
<profiles>UNSAFE_YOUTUBE</profiles>
<portrange></portrange>
<urlcommand></urlcommand>
<requestheader>Cookie:.*PREF=.*f2=8000000</requestheader>
<responseheader></responseheader>
<month active="false"></month>
<day active="false">1,31</day>
<weekday active="false"></weekday>
<hour active="false">0,23</hour>
<minute active="false">0,59</minute>
<matchmode>absolutetime</matchmode>
<addprofiles>SAFE_YOUTUBE</addprofiles>
<removeprofiles>UNSAFE_YOUTUBE</removeprofiles></profile>
<rewrite><enabled>true</enabled>
<rewrite><enabled>true</enabled>
<profiles>UNSAFE_YOUTUBE</profiles>
<pattern>Cookie: ([^\r\n]*)</pattern>
<replace>Cookie:$1; PREF=f2=8000000;\r\n</replace>
<which>client</which></rewrite></rewrite>