Another sizing up question? please

I have this pattern.
http://www.dreamweaveryarns.com/catalog/babys-silk-summer-dress-p-1674.html

I want to make it for my dd for here birthday. But I have a little up sizing I would need to do. I would need a finished chest of 25" and a length of 32" (yes she is tall and thin) Also this is knit flat and I would like to knit as much as I can in the round (faster for me).

Can I adapt this pattern or am I asking for to much? I really like the shape. I am think of using a cotton would it weigh to much?

It’s a pretty loose shape so I think a heavier yarn and bigger needles would make it bigger. If it has to be a certain size you’ll have to do the math…:think:

How would I figure out the shaping? I think I can figure out the length and the width.