As a rookie just learning to play keys I had bought a YC61 in January a week before the YC73 came out.
A bit frustrated about that, the dealer mentioned that he did not expect a 73 keys YC, well he was wrong and it took him by surprise.
Investigation showed that the 73 key version of the YC did not had waterfall keys but was actually the same keybed as the CP73 and YC88 had the same keybed as the CP88.
I was offered to return the YC61 and get myself a YC73 ... but the price is substantially higher.
Around 750 euro higher, so I asked the dealer what he could do for an additional CP73.
He made me an offer I couldn't refuse and that gave me a dual manual setup.
I connected the CP73 with MIDI to the YC61 as the YC is really geared for such a setup.
I do most of my practicing now on the CP73 with its balanced hamer keys as I think that is better for your finger muscles.
But that is not all, by connecting the analog outputs of the YC61 to the CP73 you can mix the two perfectly and have 6 voices if you want to all under the CP73 keys and master volume .... fantastic.
The only think that i need to figure out is how can I connect both the YC and the CP to the ipad so i can use Soundmundo on both .... but I guess that is a challenge.
See picture of the setup.