I usually model stuff and organise the workshop in Sketchup. Here's a less accurate approximation for the room you need.
If I ever need to go through the chuck with some very long stock, I'll put a hole in the wall. These dimensions are as shown relating to the space it occupies, not the machine itself.
Doesn't look like you had much choice!
Make sure you leave room behind the lathe so you can change and tension the belts, it's a right pain to move the lathe once it's level and bolted down as a Siamese belt keeps jumping!