Hi Tony

You have to allow some leeway for two axis so if you want those figures?allow another 50 mm to each axis,ie...

650 X axis
350 Z axis

This extra 50mm is end to end components and then will give a full 600//300 distance but still will be short due to the Y axis plate and spindle.
So think on size before you constuct and think about what you want to cut when its up and running.

The X axis could be longer in my view ie 450 at the very least.