p.s.: As some People said before - moi is good for fast create and draft designs, shape your creative minds - for such a Job your program needs deep history mechanism (Feature trees Catia V5, NX,... ), constrains and parametric abillities and/or advanced direct methods (syncronous NX/solid edge, spaceclaim, CATIA VX...) to avoid recreation the geometry again and again, till you find a good result.