Yeah, I´m late because I was going to say the same Lu has already said about the use of acrylics for the camo.
I also agree that -most hard edge camo schemes, like this one- are easier to brushpaint than to using masking tape and airbrush. The key is to brushpaint it in sucesive layers of thinned acrylics. Not a quick but a reliable technique.
Once more, I´m afraid I´m too late to suggest it but, in fact, you could try it to give a more rounded edge to the camo pattern!
Anyway, I like very much the choiced camo and the putty sand bags are a true nice touch!
I had no idea the lower sides of the turret were white painted, BTW!