Mike, your bumps are probably too similar. For the bricks, only mix the lighter values. For the Grout, mix just the lower/darker values. There needs to be enough difference between the two so that one receeds and one advances. 50 percent gray is flat as far as Carrara's thinking. Veloute is an excellent choice too as mentioned by Shonner. But since you set up with Enhance C, so did I. Enhance C is soooo versatile and so deep in features though - it's got to be my favorite plug for texturing.