I get pretty good luck on bump maps around 0.02. Hate to say this but you really have to fine tune each one. A delicate Vicki face might look better quite low. Around 0.005 even. I use the bump in the displacement node cause I don't know any better, :))and it reliably seems to work there. For buildings anything from 0.5 to 1 can work amazingly-- one reason why I love the FireFly renderer is the flexibility of the Material room and how realistic you can transform even the crappiest texture. The reason I hate the FireFly renderer is once in awhile it decides to crash when I use the Material room-- not often though, so love is ahead so far. Emily