I had a 60 sized Saphir back when they first came out (20+ years ago) (still have a SaphirII NIB). I used CA hinges on the stock surfaces (asymmetrical hinge line). There is plenty of wood for the hinges to adhere to, BUT you must make the hinge slots at a downward angle on both surfaces to provide lots of wood above and below the hinge. It is a good flying airplane (I had about 200 flights on mine when I sold it), however it was a bit overweight; in hindsight I wished I had powered mine with a YS 91AC. Someday, when I finish my SaphirII I will probably modify it for fixed gear.
Good luck with yours!
-Will