the citadel shades are made to be used before drybrush, in other words dont use them on something youre not going to drybrush afterwards.

i dont thin them and i apply them liberally, but i always follow up with a drybrush.

if you're not going to drybrush you might want to thin them or selectively apply them.

i also like things to look grimy and i dont know how to use weathering powders.