If you mean the separation between two columns - X has one pre-built if you use the "Scrolling" title generator.
Here's a screen shot of the result directly out of X.
I didn't actually try to adjust the gutter for my project - but increasing the size of any text typically alters it's spacing, so I presume that selecting the space and chaining the font size of it might alter the spacing even if the letters are in a different font size?
"Before speaking out ask yourself whether your words are true, whether they are respectful and whether they are needed in our civil discussions."-Justice O'Connor
It was a corrupt title. Have no idea why. I tried again and added another scroll title. It works as predicted now. The previous scroll title actually crashed FCP X. I deleted it and added a new one and all works now.
I don't know about you guys but I find FCP X (10.0.5) to be very buggy and unstable.