Large sigils

I’ve had some decent success with small sigils, but if I use a large sigil, if it has large lines, I have a hard time getting it to open or activate. Wonder why that is? Maybe it’s a strange Optical trick, something like that.

It could be because when you gaze at a smaller sigil, you can take the whole thing in at once, but with a larger sigil your gaze automatically focuses on only a part of it at a time.