I ended up using 16 characters/mules in all. I bought my main a random set and I have a single back up mule with the matching numbers that way if I win with my main I might take an actually piece of gear. Then I have 10 mules with the 00-99 range of marbles to win a 4th prize 100%. The final 4 mules I just randomed.
So fairly interested in seeing what others did whether anyone has actually went for the 3rd prize 100% or anything crazy like that lol.