Edge slide to coordinates

Heya people! I have some questions on modelling.

http://img844.imageshack.us/img844/3637/4buf.png

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How do I slide the circle edges to a global z coordinate without deforming the mesh?

I simply want to slide the edge there so that I can line is up with the gun trigger protection thing for bridging. Simply manipulating the global coordinates would not do as it would deform the grip.

Secondly, how do I bend the grip of the gun to the shape shown in the following with the blue highlight? I know that you can add more edge loops and manually make the curve but is there any other methods on bending it?

http://img833.imageshack.us/img833/2161/6kk.png

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Hope someone can help me with this. Thanks and cheers!

Edge Slide = GG or Ctrl+E / Edge Slide for the selected edge

Yeah I know that. But how do I edge slide so that that edge is at a coordinate? For example slide the edge to coordinates Z = -2.5?

Can’t use snapping with edge slide so either follow the coordinates on the properties panel (you can also type in the delta while sliding), or use the knife tool to cut it. Press K for knife, enable angle constraint with C and cut trough option with Z and then cut by starting from the vertex that is already at the correct height.