Hi Dene,as a S African ,let me tell you how I did mine.I learned this method when I built my sailplane many years ago and used the same method on my KR 2 S.My sailplane spars are three times the thickness of a KR and the drilling was done with standard length drill bits.using two and a jig.The wafs are accurately located and clamped and the the jig positioned,the hole started on one side,drill released.drill bit left in position,another drill bit fixed into the drill and the hole drilled through from the opposite side.,pushing the other drill bit ,on the other side, out.On the KR it is easier.as the spar is not as wide.The jig is very easy to make.It is simply a U shape steel with holes drilled to accept a pipe of the required diameter ,brazed in position,then a portion cut out wide enough for an easy slide over the spar and wafs.A good drawing can save a thousand words and ,if you forward me your address ,I would be glad to send you a sketch.If I scratch around,I might find my jig and I will send it to you. Best Regards, Eric Evezard, South Africa.