George's barriers worked one at a time. He couldn't create two or more at once. What he could do was morph the single barrier at right angles to make it look like it was more barrier than just one.
His barriers stopped everything physical from entering through it. Only light, heat, and sound could pass through. Even when intangible, everything physical was still stopped.
There was only a set amount of strength his barrier could defend against at maximum. And the power reduced depending on the surface area of the barrier, and the number of times a barrier was used.
He could also never made barriers that wasn't facing him, so there was no point in trying to create a barrier in a way that it was used as an attack, rather than to defend oneself.
If he had tried to capture Stanley in his barrier just now, he could be in trouble as the house was on fire. The shrinking of size took a long time, so he would've died before Stanley had any problems.