Abstract
A strain-first REBCO conductor architecture and a bore-resolved winding method, applied across two dissimilar machines. The central result is an honest negative: the binding constraint flips between a stress-comfortable spherical-tokamak centrepost and a stress-bound mirror plug, with the field a conductor enables kept rigorously separate from what a coil can realise. Kronos has fabricated and measured nothing; every number is a design target, model output, or literature inference.
This paper is Open Access (CC BY 4.0). Every headline number regenerates from the named script and archived data in the deposit above; requirement-class assumptions and open risks are stated in the manuscript rather than absorbed into a single optimum. No financial or commercial information appears in this work.