Footnotes for Standard Weights

Why only minimum weights?

Minimum weights are enforced because fundamentally a 2 pounds of weight contains 1 pound of weight it just has other stuff too.
Because 2 contains 1 I also don't care if the implement is heavier than normal due to terrain effects. Such as but not limited to:

Mud on the implement. This only adds weight.
Water on the implement. Whether its raining or someone threw the sheaf bag in the river on accident. This only adds weight.

Why the strange verbiage for open stone?

The inclusion of the verbiage "or equal to" is because if by some chance you don't have a second rock you may throw the same rock for both events provided it qualifies as a Braemar.