Question about low-pro gas block?

[Metal Magic]

Hey everyone,

How much space is enough around a low-pro gas block on an ar-15 with a free floated rail? I just installed a FF rail this weekend and my block is actually a shaved down front sight base. I only have about a 32nd - 64th of an inch around the top of the block. I am curios if this is enough space to accommodate for barrel whip while firing?

Any ideas? is there a way to measure? (other then looking for rubbing marks)

[Metal Magic]

Bump... No ideas or input?

[Zartan]

Any ideas? is there a way to measure? (other then looking for rubbing marks)

Feeler gauge or gauge pins