do not think that you have to do it in one continuous cut, remove managable sections
You can, but how often you have to remove the secions will depend on how heavy the unsupported part is. Once it gets heavy enough to sag under it's own weight it's time to stop and cut it loose. If you have to stop and do this too often it gets tedious, and you tend to start "pushing your luck". The final procedure usually ends up being some combination of the two.
As something of an aside, I think you're going to find that the sawdust will tend to obscure your view of the line as you work. Having a helper with a vacuum can make things much easier, and the final result much better.
All of this is simply MHO, of course.