I fitted a screen today and this post by Shadowjack was a great help. Below is a pic with the screen removed to show how the two bottom holes are slotted.Don't take the lower ones all the way out. The holes in the brackets are keyway-slotted, you just slide them down and pull them out.
No fear.I musta got lucky. Had my windscreen off twice yesterday. Noticed the slotted holes at the bottom but didn't have any issues.
They are an M5 5MM, which is a 0.8 thread pitch, 5mm opening.I read somewhere that if you gently hand start the screws into the wellnut they go in fine. Just get them started then use your wrench. I just tried it and worked great.
So these are 5MM wellnuts?