One thing that did show up when I did this one starting from the top, when forming the next louver, it tended to pull the bottom of the louver above it into the form. I have just started the second one and doing it from the bottom it stays straight and flatter as have more metal above it. So I wont use the first one and make two new ones.
The bonnet ones taper in length so I have chosen the middle one at 6" in length and made them all that length. I modified the former a bit by adding the extra piece you can see in the lighter coloured timber. What this did was make the top edge of the louvre sit down flat without twisting up the louvre which is what would happen if you just hit it down with a mallet on its own after the louvre was formed. It also further controlled the depth of the louvre making them all very consistent.
Now to set out where they will go. I held the front guard in place against the edge of the cowl so I could mark where the top of it was. I wanted the slot of the last louvre to line up with this. Then made them square to the A pillar edge. Hard to see but the hole under it has been cut out ready for welding into place.
Welded in after some planishing to correct the shrinkage from the welding. Having a matching one of the other side will add up to enough fresh air flow to feed the A/C system.
Think it breaks up that plain bit of the cowl and will function well to deliver fresh air into the cabin.