Sticking to the text is less important to me than aesthetic and cost. The scale difference between the dunlendings and orcs/uruk hai I can live with, Tolkien was pretty vague about these things after all - there's no one definition of an orc. But given that I already have a plastic Rohan force part painted, it's got to be consistent with that. I don't mind the dunlendings being bigger than orcs, but I want them to be similar sized to Rohan troops, hence my liking for Perry/Warlord which seem pretty similar to LotR (sculpted by the Perry brothers of course). The MM aesthetic is very nice, hopefully the scale will be similar but I suspect not, I am expecting them to be nearer 30mm than 25 mm as I do own some of their Norse figures.
My plan is to wait for the MM KS to arrive, then check the scale and if necessary look again.