Very nice and welcome to the world of armor building! Your debut looks fantastic.
I completely understand the reservations about muddying up armor. When I first changed over from building aircraft, it was extremely difficult to bring myself to dirty up a model because I was so used to the relatively cleaner lines and paint definitions of aircraft. Once you break through that inhibition though, it's a lot of fun to experiment and try out different things to see what effects they produce. Every now and then I still build a "clean" armor kit to remind myself that it's still possible to do.