FMT Noses' plate works as it goes under both leaves, so the outer leaf provides resistance to uplift caused by the inner oversail. Corbelling would be over so far, with the load on it it would want to collapse. Not a nice solution - assuming that it would work in any event. If ir looks wrong - and your detail does! - it usually is.
Why not do the infill at gf level, step out at first, which can be off the joists (if wall upstairs is timber?
Or some steelies, supported at set points. No need to worry about ex floor, whichever of the two suggestions above that you use.
Why not do the infill at gf level, step out at first, which can be off the joists (if wall upstairs is timber?
Or some steelies, supported at set points. No need to worry about ex floor, whichever of the two suggestions above that you use.