He reckons that with the elbow on the inside, all of the shock of impact is absorbed by the bend, whereas with it on the outside it is shared with that small section of spoke resting against the flange. Seems reasonable to me.
All out is strongest; followed by one in, one out; then all in is the weakest.
Apparently it is stronger than having them all on the inside according to this site: http://www.geocities.com/spokeanwheel/lacingrl.htm
He reckons that with the elbow on the inside, all of the shock of impact is absorbed by the bend, whereas with it on the outside it is shared with that small section of spoke resting against the flange. Seems reasonable to me.
All out is strongest; followed by one in, one out; then all in is the weakest.