According with official info, Glaug's height is 16.55 mts. In 1/72 scale, this is 22.98 cms... so if Captain's Glaug heights 35.5, x72 = 25.56 mts. This is more than the Monster, which height is 22.46 mts.
Here is the size chart:
Anyway, a couple of meters more is not problem to me, if this means a more credible result.