your design is greagt but mick64 is right, 3.5" only bays are outdated 5.25" are much more flexible
additionally i don't know ANY high quality 200mm fan out there, it'll be quite difficult to source a fan of this size -> 2 120mm are a better choice
maybe it's possible to make a 3.5" and 5.25" bay with a blanking plate for the 200 mm fan once youn install the 5.25" bays
it would be a great feature and VERY flexible :up:

