spiral staircase for loft

I think it's a not a good idea to cantilever 2x4s on lag-bolts out to 50%, or 4 ft. When weight is applied to the front cantilevered part,the rear end is gonna be pulled up; like a see-saw.
The 2x4s would also have to be x-braced to prevent them from flipping over sideways.
Double shear to a vertical member, or a jack-stud underneath it, would work on the center point, but you still need to anchor the rear end to the floor joists. Not the sill-plate and not the adjacent studs, unless they too are anchored to the floor-joists, in shear, not tension.
Well I suppose you could chain the cantilever to the ceiling trusses. Not the collar ties and not the rafters.