Please note, I'm talking at sustained speeds driving largely legally, not flutzing along at 30 under...

So, I'm stuck at 4.2l/100 on my drive to work. I really want to do a return trip one day at 3.9. However, there are a few caveats.

Block heated car in morning. 10 second warm up before departing. 2km at 60km/h. Then 25km at 95km/h, no slower. There is a required Tim Hortons drive thru, which I start stop my way through. Then 10km more at 95, then 10 traffic lights, then a further 6km to work at highway speeds.

I feel like I am maxing out what can be done, but I know dropping another .25l should be doable.

Any advice? Because right now, my only option is to lose a bit more speed, but the wife will kill me if I drive any slower.

So do I wait for a tail wind? Or do I draft? Or do you all think I can squeak a bit more out?