Thank you for that very elaborate and helpful answer!

I'm most definitely going to try the FileSizeOptimizer. I would prefer that to using Blender if possible.

I'll experiment with the seats/rows in blocks to see what works best. Probably the whole thing as a single object because they are not that big. For other furniture I will have to try for each one what works best but since I already try to create objects as small as possible they will not use that much memory. It adds up though in a whole project.

I'll report here if all efforts resulted in a workable html5view.