With the WD-814 Windscreen in place I clamped it in position while I began drilling the holes from the back and working my way forward. I inserted the bolts as I went in order to keep things tight. I would drill the hole on the left and right outer area then deburr and add the bolts before moving forward.
Lastly I drilled the two interior bolts that hold the weldment to the inner portion of the fuselage.
In addition to being an integral part of the windscreen/canopy structure....it also serves as a roll bar in the event of an off airfield landing.