Mounting a GL1800 spoiler on a Valk I/S trunk

[BOZ]

Does anyone have a template for mounting the GL1800 spoiler to the Valk trunk? It came with a template for the GL1800 which is based on markings inside the trunk of the GL1800. This is useless for mounting to the Valk I/S. I already have a rack installed on the Valk trunk and want to mount the spoiler under the rack. The spoiler will fit just fine, but I want to make sure I drill the holes in the right places. Any suggestions on how to do this "neatly" will be appreciated.

[BonS]

This is what I did:
Remove the LED brake light wiring to have a clean bottom on the spoiler.
Blue-tape the general area on the trunk lid that is going to receive the spoiler holes.
Use a stamp pad and ink the spoiler foot pads on the bottom of the spoiler.
Align the spoiler and press it down onto the trunk lid leaving your mounting hole marks for drilling.
Make some measurements from whatever reference points you like to assess your work.
I missed a few times and re-marked until I was happy.
Figuring out how to cleanly run the wire was hardest for me.

[cutter]

+1 on what BonS said. That's what I did.... 

[Kingbee]

Here's some old PICs of how I ran the spoiler  (and speaker) wires