Thanks for that. I plan to have sliding side windows so should have plenty of air flow. There's also the cut-outs in the wood side which I can panel in or not depending on if the windows prove sufficient. I'm also toying with the idea of a sunroof but sealing it will not be easy plus that roof panel is moderately structural. I'm aiming for a curved windscreen to encourage rain to go around it and fall off the sides which will slightly overlap the side windows. I'll give some thought to using a ram-air scoop and some ducting to flow air directly to the windscreen though I think I'll wait and see if it proves necessary. I could cut into the bonnet / hood just in front of the screen to keep ducting short.