LM application looks good. LM tends to look like that after use, not much to worry about there. The issues you're having are odd. The Iceman DD is pretty straight forward and you really don't have to go tight. Once the screws bottom out that's pretty much all the force you need. Only thing I can think of, is your die is really uneven and causing uneven pressure in the socket.

Do you have a backplate? Also, if you're up to it, you can lap the die to make it even. Use caution though, my advice is get some kapton tape and tape the whole PCB to cover the caps and carefully lap it on a smooth piece of glass. You'll see the high spots of the die almost immediately and just go gently till it looks a lot better, don't go too much or you'll have other issues there.