Alignment of the Start on Launch switch with the timer is quite critical for correct and reliable operation. A technique used by F1C flyers has shown to work quite well. Although you can certainly develop your own method, take a look at this for some ideas. The key thing to notice here is that both the timer and the switch are mounted on the same fiberglass reinforced sub plate. This allows for removal as a unit from the fuselage for service and cleaning, and it lets you get the set up just right.

NOTE: The person who made this model made special aluminum fittings for the end of the pawl so the wire from the SOL would ride in a little groove. Although this is certainly a neat thing to do, it should not be necessary to achieve good solid operation.

Any way, this will give you a good starting place for your own installation. If you come up with something that works well, take a couple close up digital photos for us to share with fellow modelers.