Used Weld-on. Two person job on first one, 1 person on other 3. Weldon seems to set fast but it actually dries a bit while still very workable - but then it sets pretty quickly.
You want to apply enough to outer edge of fuselage recess to squeeze out. I used 50% acetone and 50% mineral spirits to clean. Clamp in place, then clean until it sets. Work slowly so you don't get strings but don't take a break for coffee. Then remove clamps in about an hour. No cracks.
One key to a good fit is to make sure the lip is ground down so that no part of the glass is above the level of the surrounding canopy. A little lower is fine but higher would seem to cause problems later (written 11/26/2010)
Use a mask that you can't smell the stuff thru is my advice. That paper mask doesn't do it. Used 'organic' cartridges in better mask. Ventilate well too so you don't stink up shop and dispose of considerable leftovers in covered container.
