Looking for a New Cartridge

It seems to me there may be a much better way of looking at this. You already have a known top-flight cartridge. Why waste time chasing down the few cartridges that might work well with your arm? It seems to me the arm is the weak link. Always improve the weakest link is my approach. For the same money you are looking at spending on maybe the right cartridge you can buy an Origin Live arm that will make not only your Koetsu sing, but anything you put on it.

Origin Live are a breeze to set up. They come with a great interconnect hardwired, eliminating connections and the expense and hassle of matching cables. That's what I did, and my Conqueror is so much better than the Graham it replaced its not even funny- despite the Graham running some very expensive interconnects custom made for me by Ted Denney!! I seriously doubt you will run into any cartridge incompatibility problems with any Origin Live arm.

I have the Prime Signature with the Cadenza Bronze base on VPI’s recommended cartridges for it, and the sound is fantastic.  I do not see why you would be disappointed with the Cadenza Black, but wonder why VPI did not recommend it over the Bronze.  Possibly about the same performance for a good bit more money??  You might want to contact VPI directly, and get their input. 

I have two VPI Prime Signatures and have used two Koetsu carts,
the Vermillion and the Rosewood platinum Signature. Set up properly both sounded great. I also have used several Benz Micro carts and their sound fine but bright. Finally I settled for two Van den Hul carts- the Stradivarius 
Signature and the Stradivarius Master Signature. They simply are outstanding. Each of the carts were not that difficult to set up if you know 
how the arm works. However each cart has a very different signature with the Koetsu being warm and less detailed. My belief is that the VPI arm will accommodate most carts. I suggest adding the Soundsmith
weight system to make the setup easier. Choose the cart that sounds right to your ears and set the VTA properly.  Some carts like the Soundsmith and Benz are very bright and others are more balanced.
Anyway since your VPI is a state of the art turntable, it is the cart that will
have the most impact on the sound. 

Browndt thank you. I also think that the soundsmith is a little not to my liking. I will see where I can audition the VDH. The problem with buying a new cart is it is a blind purchase most of the time. I am in the NY tri-state area and find it hard even here to find a retail store that has more than a couple of cartridges set up. Unless you have a friend that has what you are looking for already it's tough 

My journey continues.