Shane,
Please do send me a link to your stuff! I'd like to have the option to have the old ammo box in at least the round emplacement. By the way, the dead model of the rounds kept the box!
In my case I used a burlap/hessian texture having a finer weave, which is an attempt to retain a sense of scale.
I know what you mean about the 'bleed' over into the green portion corresponding to the box. I didn't find it objectionable enough to compensate for. (I don't generally build dioramas for close inspection; my emphasis is on what can be seen from the cockpit as I range wildly on my rampages of destruction.
) One could easily slightly adjust the material mapping X coordinate values; in a spreadsheet this would take but a few minutes.
While I'm playing around I should undertake whatever refinements are warranted.