The XXL enclosure I built for my son is 54" w x 48" d x 24 3/4"h, If I were to build it again, I would add another inch to the width.
His SO3 enclosure is 38"w x 33"dx24 3/4" h, this allows for an extended sacrificial bed to carve full 16" x 16", I would add 2" to the width of this if I were to build it again.
His XXL is sitting on a wooden workbench built for the SO3, 36" to top, the SO3 is sitting on a Kreg mobile bench 39" to top. We are both over 6’ tall, I prefer the SO3 height of the added 3". The Kreg bench will allow you to adjust the height.
His enclosures are built with a hinged top/front door of 24 3/4" tall/deep with gas springs so we have better access without hitting our heads on the door.