> Hann sá Þorgerði hölgabrúði sitja og var hún svo mikil sem maður

roskinn.

> He saw Þorgerð Hölgi's-bride (a giantess, presumably an idol rather

than the real mccoy) sit(ting) and she was as large as a full-grown
person (but given that she was a giantess this makes the idol a
miniature!).

Could be... The First Grammarian mentions her size in one of his
examples; in normalized spelling: Há dó, þá er Hölgatroll dó "A tall
woman died when Holgatroll died." That said, I wonder if the idea of
her being gigantic was something that only arose later when Christians
came to associate the name with monstrous and demonic creatures, or
whether she was seen as exceptionally big by worshippers too. Here's
an article with some background on Þorgerðr Hölgabrúðr. It lists
other references to her in Old Norse literature and summarises
scholarly thinking about her.

http://www.dur.ac.uk/medieval.www/sagaconf/rothe.htm