Hi,
I have some on the painting table at the moment. I think they look good with TAG, Warlord Games and Empress. Empress are more slender - mure realistically proportioned that the standard wargames figurres.
I use Foundry as well which are considerably smaller, and 1st Corps which are on the shorter side but I think they have character. I vary the heights by putting card or mounting board between the base and the figure - as long as the head heights are roughly similar you don't really notice that the feet are higher, and I think the variation in poses and dress really suits the TYW. By the sound of it once a unit had been on campaign for a little while they would have been happy to wear anything they could get, and it was perhaps the last major european conflict before uniforms began to characterise regular armies.
Here is a comparison photo, showing Warlord plastic conversion, TAG, Empress, !st Corps. Perry, Redoubt (very big), Foundry, Emil - Hope you can see the attachment, it's been a while since I did this.
Alan