Hey Bataleon,
I ONLY coast in neutral. Because I mostly travel highway and most of the time in near peak-time traffic, losing brake-pressure is not an option for me either. I can live with the likely 0.6-0.8L/h burn rate. The Bantam's Odo is electronic, so I don't know how it'll cope with a kill-switch. No EOC for me. It's the 1.3i.
Be that as it may, I've been averaging 6.24L/100 since bought and completed 2014 with an average of 5.98L/100. My record down from Pta to Pmb is 5.2L. I run my tire pressures at 2.4 Bar and up to 3.0 (the limit) on longer trips, as keeping it at 3.0 on this already stiffly sprung vehicle is a bit harsh.
I don't travel particularly slowly, mostly driving between 100-110km/h, but you can score A LOT with coasting when you can. Also note my lower grille block, which is fine even in the hottest weather, as it doesn't really block the radiator, just the extra.
Not shown in the picture is a solid tonneau cover. Good luck with your ecomod adventure.