There is such a huge amount of space available I don't usually have any of my plots close to each other, if fact it's usually easier and cleaner not to.

For me
Drive A starts at nonce 1000000000
Drive B starts at nonce 2000000000
etc.

If I get a bad nonce from the miner logs, I know very quickly which drive on which system caused it. There are huge gaps but they don't matter at all, and no overlap will ever occur.