Hey, no problem..
Can you take some pictures for us to help you to see what there is to work with? Maybe a pic of the fuse card, and a pic of the fuse box.
The fuse tap doesn't stick out much at all, and the v1 hardwire cord box isn't that big. I'm sure you can tuck them in somewhere..
Where are you trying to locate the detector, up near the rear view?
Oh, and post a pic or two of the whole car..
As for which fuse to tap, anything off the top of your head (maybe accessory wise) that turns on and off with the ignition? Do your 12v socket's turn on and off with ignition?