I have very good totally uniform black and white and toned monochrome results with the Z on both Hahneumhe Photorag Baryta and the Canson and Hahnemhle matt papers. I've never used their internal color wheel, and never would unless I was doing split toning or something. It is the slightly better color gamut of the other printers that would entice me, along with the amazing speed of the Canon, though I've never used one.
With the Z I assign an srgb color space to the file - create a Hue-Sat adjustment layer in Photoshop - assign a value of Hue-40 Saturation-2 and I totally match the hue of the Cone Neutral K7 print hue on the same media. If I send the file over there Grayscale or RGB with no colorized adjustment layers I get a nice selenium tone that does have a very slight split to it like selenium normally does, but it is very subtle and I like it. If I want any range of sepia I just crank up the saturation and use a hue somewhere between 20 and 40. I'm not seeing any crossover there either. But really I've used monochrome inksets for about 7 years and I'm very satisfied with this method. However, I do wish we had one more gray, a light, light, gray to equal the subtlety of a dedicated monochrome inkset. I don't know if that day will ever come with any of these printers, at least not in this economy. I would trade my blue channel for it.
john