custom or practice?

[roseriver1012]

it is the ____ for Englishman to raise their hats to ladies to show their respects and politemess.
Should I use "custom" or "practice" for the gap here? And why? If possible, could you tell me the difference between these two words in this sense? Thank you!

[Soup]

it is the ____ for Englishman to raise their hats to ladies to show their respects and politemess.
Should I use "custom" or "practice" for the gap here? And why? If possible, could you tell me the difference between these two words in this sense? Thank you!

I'd use "custom" in that context because the context refers to culture. Note that, a custom is a long established practice.