8-bits synchronous up counter with arbitrary sequence
As you have a way to load your counters with a value, you would be resetting the upper counter, and loading the lower with 24, 1100b

to load a value you need key[3] high, key[2] high, and Key[1] low, on the next clock edge of Key[0] it will load the value from the SW[0:3] you would have this wired to be 1100b or 24, while for the other counter you would have Key[3] low to reset the counter,

Here is a simulation link for the single counter subsection, to give you an idea what each signal does, 

Falstad Circuit Simulator Link