Door question from Rod's book

I'm doing my first door frame and noticed the 'Double door assembly' on p.96 (Figure 5.7) shows only one 'king' stud (or is it a 'trim' stud?) on each side of each door. Will that suffice in this design? (Due to the 5/4 Jamb & 1x4 casings?) I notice 'generic' door plans with a King stud on each side, plus a Trimmer just inside of that for the 'Rough' opening. Also, other plans with on this site with TWO kings on each side plus a Trimmer. Any help would be greatly appreciated. (And if you have any suggestions on my thread below, 'Wall construction question', I'd also greatly appreciate it.) http://www.johnlsayers.com/phpBB2/viewtopic.php?t=10340

Think of the King stud as the one that goes all the way from the header to the baseplate. it provides the strongest point of support against vibration back and forth. The king provides the most support... The jack is what "jack's" up the header of the door or window. From what I know which is a modest amount with sparring moments of clarity in design... I would use both for stability. It's just good design. I've even doubled up on the king studs because I wasn't sure what type of door I'd be using and whether I'd have a door closer on it. A closer, slows the door prior to it shutting and avoids those cursed slams that can take off limbs... Here ya go: found this when I got thinking about whether that 5/4 door jam could possibly be providing the support.. http://www.taunton.com/finehomebuilding ... -wall.aspx