Someone else will have to help with weights of known Holmegaard examples. From what I have seen where weights have been given, the Cascade ones are significantly lighter perhaps as much as half the weight or less.
This may be purely because the only ones I have seen are single colour i.e. not white on the inside and not cased in clear glass. I now have two of these and they are virtually the same weight. Both are single colour and uncased.