As title says, it seems size is capped at 150, as text doesn't become any bigger after that.
Examples:
This is written in tiny size.
This is written in small size.
This is written in normal size.
This is written in large size.
This is written in huge size.
Examples:
This is written in tiny size.
This is written in small size.
This is written in normal size.
This is written in large size.
This is written in huge size.