skyclamp
Given 5/2/5/4 you won't be flying on day 6, you'll be doing SEPs or non FDP stuff.
I have to say I'm no fan of this proposal but, overall, I think folks are making far too much of it.
4 sector day - do 2 in each seat by mutual agreement and go home - not exactly difficult, dangerous or over-fatiguing.
Talks of potential CRM problems are insulting to professionals.