Looks very good. I personaly though would take the 4bo and add just a tiny bit of a light tan(radome tan is a perfect color) and paint the top of the bolts with it, which would add depth, and won't look out of place(unless you add alot of tan) as well as a dark brown wash(devlan mud from citadel or sepia wash from vallejo are both very good acyrylic washes). Or you could leave it because honestly looks just fine as it sits. How much of a difference in size would a 1/16 tank be compared to the sa,e tank in 1/18? Is it like the pte abrams VS bravo team abrams, or is it not noticable unless examined thoroughly?