For a 200+ gal I think a P. heptus is a better choice. The Z. desjardinii average size is 16" long and almost that tall. They are also quite large eaters = waste producers. Large ones can get 18" and be rather bossy. Mine can eat a whole Formula1 frozen cube in one bite and 3 of them without stopping.Maybe I'll go with a couple of hippo tangs instead of a sailfin.
The image below was taken 6/03. It is a few inches larger today

HTH,
Kevin