1.  I have switched from a projector lamp mount bolted up to left gear leg (used for 6 years) to Tim Ong's Airlite, a much prettier solution that can be aimed in vertical and horizontal planes.  See http://www.leadingedgeaircraft.com/

 

2. The problem is that 100W halogen lights have no cover while the supplied 75W does.  For many of us, lacking the eyes of a 20 year old, 100W is a minimum to provided and adequate amount of lumens.  At the suggestion of another LML'r, I went to Edmund Optics:

 

 

for a float glass window 49mm diameter x 1.5mm thick (1.93" x .06") that costs about $15 (part no. 30971).  After several test flights and taxi operations, the cover is still whole.  Note that the next size, 51.5 mm (2.03") is a bit too large.  Also, Shannon lost a screw-on reflector holder and I did note that because of the cover, the "cap" is not snug even though pressure is applied by the o-ring.  I did apply a drop of Loctite 242 to the threads.  My original 6-year-old bulb is still operating and I expect it to continue to do so.

 

3. Bulb choice depends on one's needs.  I use the Lancair designed cowl mounted GE4509 100W to light the runway during approach and the wide angle Radiac EMC 100W "flood" to light the runway outside the pilots window after the flare.  Marshall's special GE 100W bulb is more of a spot light than the EMC and, if one mounts Airlites on both gear legs, the spot on the right leg might provide optimal light during approach and a "flood" on the left for touch-down and taxi.  Or, one could mount 4 lights as Shannon did so that the whole county can be illuminated, thus giving the pilot more ground contact (landing) options.