Hi,
The way he has demonstrated it in the thread you sent is pretty good as it happens.... You can ground the device to any metal screw which screws into the metal body. For the live, he has used a spade connector to connect straight into the fuse box. Not sure I woud do it that way... Normally there are some runs of blades along the side of the fuse box which has two sections, one perm live and other ign live. I can't see that in his diagram, so you may just have to use an empty slot.... Do ensure that the current drain is not too high with what you are using.....
Devices like Tom Tom and Road Angels don't use much power, so they are OK... Perhaps just use a 5 amp fuse (or less!!)
An inline fuse is good also (as shown in that diagram in the other thread)
If you make the connections like that, you can firstly run the wires to somewhere in that area and drill a further accessory socket in the dash with a small toothed holesaw.
Having said all that, personally, I would just get the adapter and plug it in the socket in the ash tray!!
