Here are some pics of my dual modded setup in case you wanted to see some.
Here is a close up of the db 15 connector that i have all my signals hooked up to for easy swapping between hitbox, astro, and mk panels.
Here is a closeup of the pcb
You can see i removed all the white housings, this was so i can easily wire up the directions and signals to the db 15 connector.
Here is another closeup,
you can see that even though the housing for the directional buttons has been removed and the prongs have been soldered, I am still able to hook up the directional wire plug so i can mount my ls 32 without having to hack up another wire to connect the db 15.
Also you can see that the power cord is hooked up to the main pcb but it is not hooked up to the usb wire. I cut the the D+ and D- cord from the connector and made it so the power and ground cord were only coming from the wire then I wired it the the 360 so that the ground and powers are connected.
All the dual mod wiring is on the bottom of the pcb and if you wanted to see it i could unscrew it for you to see but it is not a really complicate mod. All the points are easy to access. just make sure you are careful when dual modding to the home button and select button.