Relevant???
I don't think there is a good website that contains the info you are looking for. There are a lot of mentions of clock ciphers here, because there was a hunt called Secrets of the Alchemist Dar, and a lot of people thought there was a clock cipher being used in it.
My understanding is that you set the alphabet around the clock, removing (or combining I/J and P/Q) 2 letters so that you have a 24 letter alphabet. There would be 2 letters per number around the clock, and the hands of the clock would point to the letter needed. The hour hand could indicate the first half of the alphabet, and the minute hand the second half, or vice versa.
I don't know if this helps you or not. There are many possible variations for this cipher, especially if a keyword is used, or a scrambled alphabet.