@Wu
About those 6 extra pages:
I would say it depends on the content.
If it is just some kind of advertisement by using the characters to make some jokes or so, then I do not care about them.
If it is just some 4-koma jokes then I also do not care.
However if it is some kind of extra chapter with info/explanation about something happening in the main story then I would like to have it.
For example in the main story the MC defeats some enemies and seems done with it.
But in the extra chapter the person (maybe a rich merchant or an influential noble) who is the actual mastermind behind those enemies obtains the information about his lackeys being defeated.
Thereby the extra chapter then shows that the issue with those enemies is still going to continue.