Thanks for the ideas Von Koss, I started building the Sisters of Tiamat, even though I was thinking I should wait untill I finish painting all my Warriors.
I cut a 60mm X 100mm and there is just enough space on the sides and a nice amount front/back.
To get the Warriors and the Starved to line up I have been bending their tails and heads and arms, but I think next time I will try different base heights as well.
I have some early progress photos now. I have been taking a long time with this painting session largely due to my efforts to paint more than usual at once.
Here are some Starved, the back ones are to be mounted on some cork, I will post a proper picture of the unit when it is complete.

The next is my second Warband mounted on square bases, I am not sure what I will do about my other round based Stygian, perhaps just glue cardboard on the bottom and putty the base square.

I am really likeing the Great Warrior, the model is really big. I green stuffed the tip of the Lance as it was a little blunt, and added putty to the base to try and make it look like the Great Warrior is steeping over rocks, I dont think it turned out great, but I am happy enough with it.

I have almost finished a Guardian, and I am really happy with how it is turning out. I am also working on a Tree Devil which is looking okay, I am liking my small alterations to the model as well.