I have these pics if they help? might have more soon to help but they show a Wargames Atlantic Irish warrior in the first pick with Gripping Beasts and then he is also compared to Victrix in the second image, so you can kinda gauge the size
I can say they are VERY close to my other 28mm victrix sets, the GB heads make them a slightly more diminutive but if you swap the heads it's not noticeable, especially from 6 feet away when gaming
lol
Some victrix models vary a bit too, some have wider chests, some have baby arms, depends on the set. I have a few roman sets and happy to answer questions on them
The GB "puddle" is also a little higher then victrix ones, something to consider maybe