Thanks Paul, I used your technique, and it works like a charm.

In the meantime I foun the Robart's Hinge Point Drill Jig absolutely useless[:'(] It centers the hole base on the wing thickness. When the thickness is not changing linear hinges will be not in a straight line. It is much easier to use ruller.
As for drilling there is no way to secure the jig so it doesn't move when drill force is applied. For me, it was just a waste of money.[:@]

I have a question tho. I use the biggest one. My TE is 3/8 thick, so I added a balsa block inside the wing to have 1-1/4 'meat' for the hinge to stick to. It is only balsa so I'm affraid it will be not strong much. Can I pour thin CA inside the hole before I glue hinge with the wood glue? I don't mean to use CA to glue hinges, just to harden the surrounding balsa.

RysiuM