I'm not a big WWII aficionado, but that's some solid work right there. Your weathering is just the right amount. Some people go overboard, which is fine if you're making a dio of a boneyard, but otherwise, it needs to be subtle.
Love the yuuuugeeee tailpipes on that first one. The rust-work is just right on those too.
I am a firm believer of not overdoing weathering and rust .
Almost every model you see has a rusty exhaust system.
Unless sitting in a field for 5 years they would NOT be that rusty.
Go out and look at your cars tail pipe.
It is gray, so my exhaust are grey with a tiny bit of weathering and heat burns.