I have found a way to easily modify the newer 9V DC adapter jacks the are included with the more recent vintage BYOC kits. The old 9V DC adapter jacks included in the kits had a flange that fitted on the outside of the enclosure and was fixed in place by an internal plastic nut that threaded onto the inside portion of the jack (terminal end) and tightened against the interior of the enclosure.
The 9V AC adapter jacks the are included in the newer BYOC kits now have an external nut that makes it easier to install IMO. However, the threaded end of the jack protrudes about 1/8 to 1/4 inch outside the enclosure - not a good cosmetic appearance and also a risk for damage.
What I have done is go to the hardware store and purchase some #9 Neoprene O-Rings to "thicken" the flange.
Fitting two #9 O-Rings over the threaded end of the jack allows it to protrude from the exterior of the enclosure enough to thread on the external nut.
The threaded end of the jack protrudes just enough that it can be tightened and flush with the nut providing a better cosmetic result that is less prone to being damaged accidentally.