http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=319136752&searchtext=mirroring
to determine the orientation of you blocks you can just use F11 ingame and select the debug draw options ;-)

for the model i suggest you to cut the edges and make it more tube-like or full suiting blocks (using the default block shapes and textures - ever wanted a inverted corner with integrated conveyor system^^)

greetz brd