To address your concerns, in my Last post I have put that it ways 730 grams, that is almost exacterly as much as the giant Swiftech MC 462A Heatsink.
The clearence for the nuts isnt great but it shouldnt be to bad as its to be used tihe the Danger Den Maze 2 style mounting kit and the nylon bolts are flexible and allow for bending.
The roughness of the channels was cuase by me having to use a CNC machine with outlube as the other machine was broken by peopel cutting wood on it and jamming the lube pump
I have left it as it was to help give more turbulance and surface area.