The old adage "measure twice, cut once" can be extended to cover orientating twice and drilling once. Eagerly pressing on as I was after Tuffcabbing the whole cab, I put the corner protectors on the back corners, drilled screw holes for all four, and then realised that I'd put them the wrong way round and the drill holes should have been on the sides and bottoms, not the back. Holes drilled in the proper places and corner protectors fitted, and a little wood filler to fill the holes, which will be given a dab of Tuffcab.
Doing a test fitting of the grille, I found it was very slightly oversized - a mm or two. I have assorted implements of destruction to rectify the situation - I think an angle grinder or bench grinder would be a bit extreme, a power file or belt sander seems more appropriate. Does the BC massive have an opinion? Just holding it on edge is going to be a bit tricky. I'm inclined to the power file (more suited to one handed operation).