Of course you could do this on 18. To get the size you divide the number of stitches by 18 so:
400/18= 22.2 and 299/28= 16.6. This is beautiful.
Kris

This is indeed beautiful! Since childhood, I have disliked pinks and purples. I think I figured out that those were girl colors, as my only sibling, my brother, said. I followed him everywhere, but that upset him. He was very clear that he could not play with me unless I wore jeans and boy clothes.I could now just want to dive into this design and love the soft clouds of purple.

If you decide to use the 14 ct think about using 3 strands of floss. I started a project with lots of purple and did not like the coverage ( or lack thereof😉)

Thank you ladies for your input. I do prefer in some cases to have more ct. per inch. I think the image is crisper and you do get better thread coverage over the fabric. I also think this Heaven on Earth project looks absolutely stunning. I can't wait to order it and get started.

Don't forget to add 6 inches to each dimension for framing when purchasing your fabric. Using 18 ct. you will need a piece of fabric 28 inches x 23 inches. It is a beautiful project.