I totally know the feeling. actually if you are interested, i had the same kind of feelings about that too when i started heavy weathering. initially i spent a lot of time adding on, and wiping off tempera paint (as it is water soluable so it washes away if i want) i trooped around like that for a few months and thought it was still too muddy.
so i ended up ordering some earth colored liquid pigment, that is actually like a sandy powder you can order and apply to your already weathered armor with hairspray for a REALLY awesome been out in the sand storm for days upon days effect.
below is a link to the site where you can buy the "dust/sand/stuff" not bad.. like $5 a bottle. might need to get more than one. i would definitely so with a larger amount of "yellow ocher" and a little bit of "slate grey". You basically need one of those sponge brushes (dry) and a can of odorless hairspray. spray the area you want the stuff to stick to, sprinkle it on, and lightly dab at it with the sponge brush. works like a charm. its kinda messy at first, but after one troop its pretty stuck on there, and will continue to weather naturally.
http://www.thedentedhelmet.com/davin/replica_weathering.htm
this is a tutorial to help you do it.
just a suggestion of course. i just thought id say something since i was in the same boat as you were and this made all the difference.
here are some pics of my armor WITH the earthtone sand.
http://i4.photobucket.com/albums/y112/phil...06/IMG_0489.jpg
http://i4.photobucket.com/albums/y112/phil...06/IMG_0488.jpg