Considering that he doesn't have to disassemble the ENTIRE kickstart to get it working... and has a professional disassembler for the 68k instruction set that supports the Amiga Hunk format... I'd say it shouldn't take long to get it done. Did I mention that the splitting of the ROM image into its constituent libraries with the ROM Split utility took a single click of the mouse to accomplish?
It's not a question of ability. (He probably talks a lot bigger than he walks.) It's a question of having the right tools for the job.