I have them beside each other at the bottom and gave it a few swings last night. I was really tired so I haven't tested to make sure. Problem is that 2 locks will ultimately limit the weight to probably about 10lbsx6plates.

There are spin lock collars with an additional bolt, so you should only need one

https://www.amazon.com/gp/product/B08K8CGG37

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I noticed the ad for the product shows one collar on top and one on the bottom, which is pointless b/c there's already a bit of a collar on the top.