I only have one lift table, but three bikes.
One bike is usually parked on the lift, and one right next to the lift so I have to move it to work on the lift.
The remaining bike is usually parked nearby. I've never had to move it in order to work on the lift, and it's never interfered with the work I'm doing on the lift.
Anyway, I just went out and measured and this distance is 5-1/2 feet from the edge of the lift to the other bike.
So I'd say 5 feet would be perfectly fine. Maybe give it another six inches or a foot if it's convenient and you're not going to squeeze the other side. A little distance might make things easier if you ever need to work on a three or four wheeler, or a lawn tractor or something like that.