>which could explain the differences in hole sizes found
There were multiple denominations of Roman coins, and I assume some variance in size at each mint over the centuries. That could explain why each hole is a different size, and why the sizes aren't uniform between each one found.
There were multiple denominations of Roman coins, and I assume some variance in size at each mint over the centuries. That could explain why each hole is a different size, and why the sizes aren't uniform between each one found.