Very good
I don't have facilities to melt aluminium (yet..).
However, some time ago I used
Aluminum angle 40x40x6 and formed a channel from two pieces like on attached sketch, joined together by couple of screws.
I also beveled the edge that goes into dovetail receptacle, however this is not strictly needed, because once the screw is tightened, the structure can't go out of the grip.