Thanks for the comments everyone, greatly appreciate them and they help out a lot.
As for the clay...I'm not a fan of the marble look but I was way to anxious to start sculpting and will do a melt and mix of the clay after I'm done with the bio and two other sculpts get finished and molded. I have a crock pot, just need to figure out how to mix it correctly.
Small update!
Sorry that it's hard to see, but I tweeked some things on the left side of the bio. I adjusted the areas where CoollKotton mentioned as well as added some gribles and stuff on it as well. I shortened the jaw thing on the side of the bio, made the circle areas smaller, adjusted the angle back a little on the tubes coming from the cylnders, made the cylinders a bit thicker as well, and I brought the back of the jaw up too. I'm not going to over do the bio and going to try and leave it clean like the concept art. I think I'm getting closer to the concept art, or as close as I think I might get without bringing in the bottom of the snout.
I'm going to be molding the tri-laser unit, the hose adapter on the left side of the temple on the bio, and the two larger blade/hooks seperately from the bio since I think it would be easier. I'm in no rush, but I hope to have him molded and cast by the first week or two in July. Not sure what masks it might fit, perhaps the monsterroom and xdmray half masks and the dome looks like it might fit usurpers P2 mask too.
I really hope I do Rob and his artwork justice.
Onto the pics.