I saw the pics...I like the color very Rusty...... I still don't have a good answer for you. The best thing I could come up with would be to draw/print out the Rad symbol then adjust it so it looks like is was poured on. Then use a small ball point Dremel tip and etch the pattern into the case (with all the bondo texture you could sink it in 1/8") Base coat it the same as the case. Then take some color (I don't know you color combo) Like glowing green (could even be glow in the dark green) rub it into the etch (use a rag get it into the crevasse). then take a darker color (shade it so dark green) and get it on most of the high spot....put it dry brush style (this is where you get paint on the brush then wipe 80% of it off then start to paint with it) Once that's done you just want to weather the whole case together (mix some brown with water so it's thin and put it on , same with black)....The thing about weathering ...if you can tell it's there you've got too much on, you want it to be very subtle, let some of it run the n use a rag to wipe it off (the dark colors will get into the deep groves and cracks but you'll clean it off the high points)...so it looks like years of neglect not poured paint!
Here's a link to some Weathering Tips
I'll see if I can find a Rad symbol and show you what I mean...
Let me know if this helps!
Crazybillybob