Will be interesting to see the star testing results. May well be that things are really good with a small chip. But as these reducers also correct for the inherent coma in the SCT design, larger chips may show a soft outer edge. Also, this SCT reducer-corrector is designed for an f/10 light cone which is sharper in shape than that of f/7.5. This will introduce some aberrations too, but one that may be fine in smaller chips, but problematic with larger ones again.
Ultimately photographic testing is the proof of the pudding. Looking forward to your results!
Alex.