Drilled conduit holes in main ribs and deburred. Countersunk outboard holes in W-907A aft spars. Made Leading edge cradles. Assembled right leading edge.
I am going with the conduit option, though I have not decided what lighting set-up to go with. Not to put it in would seem to limit my options. There is no guidance as to the optimum placing of the 3/4in hole for the conduit so I placed it by eye in the centre of the area suggested by the instructions downloadable from the Vans site. I initially drilled a #40 hole and then used that to back-drill a scrap of aluminium jammed up against the lower flange and placed with its edge against the the edge of the vertical stiffening indentation - basically any landmarks that were convenient and would be the same on every rib. Using this template, I put the same #40 hole in every rib and then opened them out to 1/4in - the minimum dimension on my unibit. Then, I opened the hole out to 3/4in with the unibit before finally deburring the edges of the hole on both sides - not that they needed it much as the unibit gives a very clean hole.
Countersinking the spars was a step I had left out so I decided to catch up on it now. I had to research how to approach the need for flush rivet heads on the outboard doubler holes that go under the outboard aileron attach brackets. The .040 material of both the doubler and spar are too thin to countersink for a #30 hole though that material can be successfully dimpled. I did not want to also dimple the aft flange of the nose rib that gets riveted with these two so I decided to countersink the spar which is the 'meat' in the sandwich comprised of the doubler and the rib. This will leave a flat surface on the forward face of the spar under the rib. 
The countersinking operation is standard except that the top hole is too close to the flange of the spar for the countersink cage. It is possible to cut away the flange of the cage to get closer but I did not feel like doing that so I removed the cutter and used it in the hex adapter that is normally used for the hole deburring cutter. The slow electric screwdriver was not giving good results so I switched to the the high-speed air drill. This was still not nearly as good as the countersink cage but I think it is easily good enough for this situation.I made the cradles from the HS cradles. There is plenty of timber in them for the size of the leading edge. I used a rib to mark out the shape and then cut outside this line with a jigsaw to allow clearance for some padding. As it happened, I was out of duct tape and decided to go ahead without the padding anyway. This didn't work out so well as the cradles were loose around the leading edge. However, the blue vinyl was (just about) enough protection for the time being.
I began by attaching each rib in position on the skin with the two forward-most holes on the bottom. This was done with the skin out of the cradle and was just to fix the ribs reasonably firmly in the right positon. Next I put the assembly into the cradle, which forced the skin to wrap around the top of the ribs. Getting the rest of the holes to match up was a real pain. The temptation to use the awl was huge and I did, in fact, use it to help line things up. However, I did not exert any leverage on the holes that would have come close to damaging their edges. In any case, the match-drilling stage should sort out any minor imperfections caused by the awl.
Having done the whole leading edge, I became suspicious and found that I had the right hand leading edge skin but the ribs were for the left leading edge. They were all facing the wrong way! Swapping them around one-by one turned out to be slow. I probably should have just started again with the left skin. It took the best part of an hour to do three of the six and at that stage it was long past time to quit.
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