Thank you Ivan, you're right with the mesh, I've already changed it.
For the cabin, I agree that it looks a bit too thick. But I think these bricks offer an elegant way to realise the sidewindow. The rigid hoses might be an interesting alternative, but I'm not sure if I could get the radius at the top corners small enough while keeping everything in position and without using too much brackets, that would destroy the overall impression. Is there a way to mould these hoses? Maybe heating them up?
By the way there is no specific scale, i tried to fit the crawlers into a picture of the sideview and adapted the rest to that. ;)