Where to cut drywall for doorway

[Felix247]

I am in the process of widening a room and moving the doorway. The position for the new doorway partly overlaps the existing stud wall and partly overlaps the new section of the wall (still to be constructed).
The plasterboard has been completely removed from one side of the wall.
On the other side, there are two sheets of skimmed plasterboard. The join is above where the door will be and I can't see any cracks along it.

I'm not sure where I'm best cutting back the plasterboard to to form the doorway.

Should I just cut out the doorway from both sheets, cutting both existing studs to form cripple studs above the door?
Or should I remove the right hand sheet completely and just cut out a small section of the left hand sheet for the doorway; again cutting the studs back to form cripple studs.
Or should I cut back the plasterboard right back to the new stud forming the left jamb of the door?

Advice gratefully received.

 

[Jake2021]

Have you a photo ?

 

[Felix247]

Hopefully the photo makes it clear what I'm attempting to do.
Wall is to extended out to the left of the photo, with new doorway going in.
I've already put in the new stud at the right hand edge of the new doorway (I'm actually doubling up on studs as I tend to over engineer).
Two sheets of plasterboard on the other side meet on the stud I've labelled; and I've started to cut away the left sheet back to this join.

Should I cut away all the plasterboard back to the new stud(s), or leave in place that what is above the new doorway?