I am new as to washes. However I use both enamels and acrilycs for base coats( not at the same time or kit) but I am using artist oils you should be able to pick these up at your LHS, they are in tubes ,the colors I am using are burnt sienna and raw umber mix at a 2 to 1 ratio with a turpentine substitude called Turpenoid, it is odorless and works great. As stated above spray the kit in a gloss coat which helps the wash settle in the nooks and creveses and brush on your wash more heavy as you go down the kit, or if you really want it dirty forget thr gloss coat and just brush the wash on. Flat coats seem to suck it up like a sponge. And always test the wash on a spot not visaible, draw back to this is if you have decals you will need to apply a gloss coat so they do not
" Silver". hope this helps and good luck.