Enabling a new inventory dimension and the AllBlank dimension Id

I recently explored the idea of enabling a new inventory dimension to track a new type of inventory in Dynamics AX. There were a few goals that I wanted to stick to.

1. Use one of the existing inventory dimensions rather than adding a new dimension. InventColor, InventSizeId, InventBatchId, and InventSerialId were all candidates.
2. While technically we would allow blank values, I wanted to have two explicit values to use rather than assuming blank was a meaningful value.
3. Due to #2, update all existing transactions in the system to be one of the explicit values.

The steps necessary to complete this are straight forward, but there are some words of caution I want to add along the way which I discovered in my investigation.