Ailatan,
After assembling the track and risers, I placed it on the deck in the exact position I needed. It is centered directly over where the old track was. I did want it to interfere with my dodger or the stowage of the life raft.
I marked all of the holes. Twelve are needed, six on each side. I drilled the first hole all the way through the deck and the fiberglass headliner. I used that hole as a reference to cut the access holes in the headliner. The supplied stainless steel backing plate was then used to draw out the area to be removed from the headliner. I just traced around the backing plate and cut it out with a 4" angle grinder. The hole should be slightly larger than the backing plate. An extra few millimeters won't matter, as the fabric headliner will cover all of this up anyway.
After drill the first hole through the deck, I placed one of the fasteners in the backing plate and put it on the deck to align the remaining holes. It worked almost perfectly. I say almost, because I had to slightly enlarge one hole that wasn't drilled perfectly vertical. After each hole was drilled, I added a fastener. That way I had a dry-fit trail so I knew everything would fit well.
Please note, the deck is cored. I removed the core from the inside of each hole using a bent nail in a drill. I then filled each hole with West epoxy. That seals the remaining core and leaves a solid glass plug around each hole. This makes sure you don't crush the core when tightening the fasteners.
I didn't take any pictures from the inside, but I will do so in the coming weeks. Not much to see, but I'll do it. Feel free to ask any questions. I hope to get out sailing soon and try it out. The car moves easily now. Such a joy.
Jake