Rail track
Not sure what or where you are referring to, Sven. Do you mean genoa track out on the toe rail? The primary reason for this is likely for outboard leads when reaching, right? If so, there may be a better solution: Put a couple of padeyes out as far as you can on the deck (and still be able to through bolt them). Put them about 8-10" forward of where your headsails normally sheet. You can run a "short sheet" through a block on the padeye to the clew, and take the other end to a free winch (cabin top?) and you can now move the clew progressively farther outboard as your sail deeper angles (using both sheets until you are fully on the outboard lead). This gives plenty of adjustment, and when you consider it would be a lot of track for just a few locations, it makes sense from a cost, weight, and installation point of view.
If you missed you completely, sorry!
Enjoy!
S