>I know of no 24hr clock, it angered them when I asked last summer.
Not sure why anyone would get angry about it.
The thing is that a 24 hr clock wouldn't make much of a difference. 60 mins per hour wouldn't change, thus 60 days per revolution wouldn't change.
The anon whose pic you show (1st one) worked with 60 markers as well as can be seen.
Unless someone explain how a 24 hr clock would make a significant difference, I'd assume 12 hrs are fine, no?