Very interesting project Hanazono.
It will be interesting to see how they progress, once you gerninate them.
I produced an interesting hybrid between Matucana Madisonorum and Cleistocactus Areispina, a few years ago.
I produced one fruit, with 12 seeds, six of which germinated. The resulting seedlings were surprising.
2 followed the aureispina parentage, but were thicker stemmed and a textured epidermis.
3 were intermediates, short cylindrical, thick stemmed, golden spined with textured epidermis.
1 was very special. It followed the Madisonorum parentage. Very pale green skin, heavily textured, tuberculate ribs, with long golden porect spines. Unfortunately it did not live past it's third year, despite appearing to be a srong healthy plant.
I will try to upload a few photos tomorrow, of the intermidiates.