Two innovations in one here that advance the cause.
I've always been troubled by the fact that cutting a sizeable aperture in the retaining plates of the upper quadcopter with which to accommodate my torso has been a significant waste of material, whether foam infill or alloy plate.
I mock up the alternative here in ply, to see if there's a solution and it seems that there is.
The central void here is sufficient to accommodate me ~ in which event the arms of the quad can be fixed to either its inside or outside perimeter.
At the same time the portion removed from its centre can be used as a base for the 'phone-booth' or flight compartment.
At the same time it also means that the upper quadcopter can be slid up the sides of the same flight-compartment into position at waist-height.
This allows for the frame to remain decidedly compact, while at the same time allowing a suitable means of ingress and egress.
Dimensions pictured are 500mm and 300mm square respectively.
All will become clear sooner rather than later...