OK wow.. I've neglected this topic a little bit. Update time!
To start off, the seller gave me the option to switch the Nagamichi wakizashi for a o-wakizashi by Hisayuki! Even though the lacquerwork had been started on the saya! He managed to sell the Nagamichi is a very short period after this. Right now, the artisan is working on the saya for the o-wakizashi in the same style as the tachi's. So right now it has become a daisho by the same smith, which is really nice (also for resale value).
The tachi was made when the smith was 75 years of age (and still working for Dai Tokugawa), the wakizashi was made 6 years later, when Hisayuki was 81 years of age. If I'm not mistaken the wakizashi has been granted Tokubetsu Hozon by the ntbhk.
When i was told about the opportunity to go for a pair by the same smith, i was also told that the wakizashi has a good chance to receive Yushuto status as well (next December). That would really be the cream on top of the cake.
High res. photo's below:
Now all that is left is to source a Fuchi & Kashira that will fit the long sword, as the first find really didn't fit it. When someone in contact with the dealer has something, work can start on the tsuka (the handles) and then we're near finish.
The tachi can be send when its at that stage, but the wakizashi will probably remain in Japan till after the Yushuto shinsa.