Will a single flameout allow a Auto-Rotate decent ? Or will it just frisbee....
Just for comparison, I ran twin Norvel 074s on a bashed 6' glider that had a final span of close to 80". With MAS 6x4 3blade props clearing the fuze by 3/4", the narrow nacelles were no big deal on a flameout on that wide wide wing. The model you're planning will be a real handfull on 1 eng.... well, that's my opinion.

Looks like a challenging project, hope you get her worked out. Post lot's of pics as you progress.