A few years ago I made an aeroscreen from scrap metal of an old solar panel. I have used it a handful of times and every single time, the urge to use it more often increases.

My questions are if half doors make a difference? And/or a tonneau?

As I wear spectacles, I confess I have been using a full face helmet. On the odd town comute I only use my normal specs/prescription sunglasses... because it is a small town.
I like the safety of a full face helmet but I definitely don't like the cocoon effect and the aggressiveness of other drivers when they see a helmeted driver. As such, and since I don't want to change lenses on 3 pairs of glasses, around every 2 years, would Davida Aviator T2, or the likes be a good alternative, or should I try a classic look open faced helmet?

I use Adidas Evil Eye Half Frames, with RX inserts when I wan to use my 'glasses prescription'.
Absolutely perfect!
The RX insert capability means I can use the one prescription RX lens with whatever 'sunglasses' lens I want, including clear for night driving...

http://www.rxsport.co.uk/categories/Sunglasses/adidas-Sunglasses/adidas-Evil-Eye-Half rim-Pro-Sunglasses/

Still doesn't stop you getting lost , should off gone to spec savers

What about half doors and tonneau?

When it's wet, I use the tonneau over the passenger side, with a 'half-door' I made from an old tonneau on the driver's side...
Works well!

Did you do the half door yourself or you had it made by a specialist?

Made myself, just by cutting a tonneau down, and folding over the top edge, and gluing it...
It means I can easily fold it up, and store anywhere.
There is no need for a 'stiff' bar at the top at all!

Not the best piccy... but you can get the idea...

You read me mind!!! I was musing about that.

Does your half door goes all the way back or you just use the door as template?

Thank you Steve!

You posted while I was writing... Too slow non-native speaker!!!

Here comes a question... As I don't have a tonneau or half-doors I need to put some poppers on the car. The problem is, I found that at least one, according to the locations on the Caterham K-Series build manual, that hits on chassis tubing. I am definitely not fond of doing this. Can someone give me some guidance?

K-series build manual Section 14, Page 6.

My car is a K-series SV, if it makes any difference.

Thank you in advance!

No problem at all having the poppers go through into a tube.
Actually, it's better, as if just in the skin they will pull-out very quickly.

OK... template/mock up done...

https://ibb.co/mnwfVn

https://ibb.co/d8kkwS

Just need to get the courage to drill... fabric is also ready to be cut.