If you’re going to put a Bomb Tower or a Skull Tower behind a barrier, if possible, put it in the corner (: From the corner, it will still shower the player and units behind the barrier, but the opponent will also have to waste a split second walking into the corner to destroy it. And not only that, but the player can’t BS not SB it from behind the barrier (: And, in making the king take the outer path, he has a harder time connecting his spells between towers.
3 reasons why (when possible) you should put your Bomb/Skull tower in the corner behind a barrier:
The opponent cannot Firestorm, Bladestorm, Sonic Blast, or Toxic Cloud it from behind the barrier.
The opponent wastes a split second having to walk into the corner to cast his spell.
In being stuck on the outer lane, your opponent will not be able to zig-zag between towers as easily, making their spells less useful.
You can also put a Poison Tower just behind that to deal extra damage when the king tries to hit the Skull Tower.