There is no set order, from what I understand. Just how the electrician wires them that day. The breaker resets on it's own so testing will be difficult. The good news is that not all of the stack breakers are 50 amp. Have someone run the slide until it stops while you monitor a breaker with the multimeter. Be sure to check the load side as the line side is always hot. My load is the left side. You can trace the line side back to the battery disconnect switch. Check each one until you find the problem. The hard part is disassembling the stack of breakers to be able to remove and replace the bad one, then reassembling the stack. If you have enough wire, put the slide breaker in last, in case you have the problem in the future. Be sure to disconnect the battery before taking anything apart.
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