I am really sold on buying a Hana SL to replace it as it (the Koetsu) must need refurbishing.
Why don’t you just buy a high resolution neutrail MM cartridge for your tonearm ? At least you could compare two different worlds of sound. The Koetsu Black is the lowest in Koetsu line and does not represent the "magic" of Koetsu sound as you can read online. Your cartridge is refurbished and no longer a Koetsu, and if you want it to be refurbished again you’re probably going to extreme, here is the thread. Hanna looks nice, but do you think it is a good MC ? Read this article, maybe you will change your opinion about MM.
This is from the TAS article:
"Everyone is entitled to personal tastes, but truth is truth. If you want to hear something like the truth, I still say-no matter what everyone else is using-that you should buy a flat-top cartridge like the AT-ML170 and avoid all MC cartridges with a rising top-end. If the sound of live music is your goal, why would you want to hear sound which is not only untrue to its source but also is something you are "seldom conscious of live.
What cartridge could have the "lowest distortion of all," "uncanny" resolution, better than master tapes?
Kavi Alexander, auteur of the remarkable Water Lily Acoustics series of analogue vinyl discs, is monitoring disc production by comparing test pressings to the master tape. What cartridge is he using? Another moving magnet, this time the TECHNICS EPC 100 mk4. But he describes the AUDIO-TECHNICA AT-ML170 as very similar, and very close to the actual sound of the tape. In this comparison, he says, virtually no moving coil does so well; most have seriously apparent colorations.
The contrast between these views of moving magnet cartridges and usual audiophile opinion is striking. On the one hand, we have assurances of these leaders of the High-End recording industry that the best MOVING MAGNETS are very close to the master tape (or live mike feed, for direct to disc) and that they are capable of "uncanny" resolution. On the other hand, we have the prevailing perception, amounting almost to a shibboleth, of the High-End listening community, that only MOVIN COILS are realistic in some sense of that word and that moving magnets are incapable of sonic truth."
This is the AT-ML170 and it’s just one example of the decent MM that killing most of the MC up to $3k retail. There are more amazing MM cartridges, the benefit is that you can avoid refurbishing or retipping as you can simply change the stylus replacement by yourself.
P.S. Hanna (aka Excel Sound Corporation) tried to steal its design from the legendary Miyabi cartridge, but Hanna is just an entry level MC cartridge.