Unless you want to go completely insane, go the decal route! BTDT, and there's just something about round stencils and my lousy eyesight that inevitably yields ... asymetrical results, shall we say?
Putting one decal over another should not yield a noticeable hump, but if you're worried about it, apply a decal solvent like MicroSol or Solvaset to really suck them down, or just trim where they butt up to each other and remove the overlapping bits.