I think i finally made a good one, its a single chamber hybrid reactor.
http://www.talonfiremage.pwp.blueyonder.co.uk/v3/reactorplan…pgc3bjnfgozupkw
Eu/t: 208
Cost: 411 copper, 160 iron, 16 gold
Running Cost: 8 copper per thorium cycle
Efficiency: 4.6