A lathe really requires you to be able to look over the top and straight down onto the work.
The two pedestal machine pictured above is not designed for sitting, it just has cabinets to replace the legs. A lathe intended for sitting at will be very low to the ground, or be a table top machine like a mini-lathe or jewelers/watchmakers lathe. If you watch someone use a watchmakers lathe, they work with the spindle below the sternum when sitting, they either have no cross slide at all and are used like a wood lathe, or have very small wheels on the carriage.
I would not operate an engine lathe sitting unless I had some really compelling reason (like being wheel chair bound). The wheel can do serious injury and pull you inexorably into the work and you might not be able to reach the emergency stop when sitting.
If you are really committed to sitting, I would pull the speed handles off the carriage and mount a camera linked to a tablet over the work. I am sure there are plenty of sensible things that out wheel chair bound brethren do that could make this safe and fun.
Honestly, if you can stand, you should stand to get things going, then sit to one side on a tall stool. Stools give you a place to rest, occupy minimal floor space, require less effort to stand up from, and work as a mini work surface in a pinch.