Your bench is basically the same design that I use. Having the flip up top enclosure really cuts down on noise and contains dust.
I can’t remember the exact dimensions that mine ended up being and I’m not home to check for an few days. I want to say that I went wirh something like 48x48 outside though. Mine is tight on the inside space a little bit. I have room for the machine and drag chain/NEMA 23 combo but if I ever decided to buy larger motors it wouldn’t fit width-wise
I have a few posts in the “workspace showcase” thread with pictures. You could check those out if you want an idea of what your design might look like.