Internal Door Frames

[Drumbody]

I've built a home recording studio and i'm using a double fire door system to increasing the sound proofing between the stud wall. I've decided to mount the door frames on either side of the studwall so that i have the studwall thickness between the two doors.

But there's a couple of questions:

Would you recommend using one of those wickes pre made door frames or make your own with some timber?

Secondly, How would i fabricate the pre-built door frame to the sides of the stud wall effectively?

Thanks for the help.