Constructing a studwall

[Dimond Geezer]

I want to construct a studwork wall, incorporating a door. I was intending to use 63 x 38 studs, with 12.5mm plasterboard & 3mm skim coat, this gives an overall thickness of 94mm. The narrowest door lining I've found is 106mm wide, a difference of 12mm. There are two obvious options available to me;

I could increase the plaster thickness to 9mm on each side, but I have an external corner in the wall & I can't find a plaster bead of more than 3mm.

I could increase the studs to 75mm thk, but I was hoping to keep the wall depth as slim as possible, and as far as I was aware 63mm is the standard stud size (it's certainly what Wickes promote as "studwork timber").

What is the industry norm for studwall incorporating a door opening?

Thanks

[welsh brickie]

cut down the door frame by 12mm.