About this cradle series, I think the perfect accompaniment to it would be basic size comparisons for each of the 3 images - I don't think it needs lineart or colouring, how much would you charge for a draft sketch? The idea would be 3 draft sketches with Hideki and Chii standing side by side, with the correct sizes corresponding to the cradle - so you can then flip between the two images, would make the cradles even more impressive.