That's a terrible dilemma. But I can help!
Get the Hana AND send the Koetsu off to be rebuilt. Then have the rebuilt Koetsu sent to me for
long short medium term evaluation. If the rebuilt Koetsu fails to meet the exquisite original quality, I can can break the news to you gently over a period of months or years. Save you that sudden aching disappointment which can be awfully disappointing. Also will save me from sending my old toddler-modded Kotesu off to be rebuilt. We both win!
On the 1 in a million chance
your our rebuilt Koetsu does indeed produce that rich transcendent musical experience that we thought we'd never experience again, I can inform you gently over a period of months or years. Again, we both win!