It all depends on what you are going to make. (read: what you can find a customer for). This determines the machinery you need, thus the floor space.
Depending on the size of your company, I like to see things split up in:
-long term warehouse (stores all the materials)
-preparing (cutting of fabrics, cores, vacuum materials, etc)
-molding (laminating, infusion, etc. Also holds all active molds, including demoulding and waxing)
-post-processing (cutting, drilling) Dust extractors are a must here. This would also be where any routing or CNC equipment would be. It is a good idea to have this close to or partly sharing with the preparation area, as you can share dust extraction and (CNC) cutting of foam. A seperate area is for sanding and diamond trimming.
-spray booth and oven (this oven can be used for postcuring as well, so again, keep this near to / share with laminating area)
-assembly (where parts are made into (sub) assemblies. Hardly any dust is generated here. Mostly positioning jigs, methacrylate glue, MS Polymer glue, etc.
-QC and packaging
This does not neccesarily fit into your business, and not all should be separate, but you get the idea. I also must say that the new companies over here that are succesful in these difficult days, all make high quality stuff, and all have their shop clean and sorted.
One other thing: I like the resin to be as much separate from everything as possible, for obvious reasons. A lot of shops I see have created a “resin bar” where they can tap what they need, without the need for dragging barrels through the working area.