setting for printing in Fresco

No, you're just wrong. You don't need CMYK in Fresco.
All what you need is a decent soft-proofing mechanism and a few gamut restrictions/warnings to make sure your RGB gamut doesn't exceed the printable gamut of a certain CMYK target and that's it. No shifts, no clips.

CMYK is not a silver bullet to produce perfect prints, and computers do a pretty bad job representing substractive mixes on a screen that is emissive. And pixels are pixels. You can repeat to yourself that a CMYK digital file is actually CMYK, but it's ALWAYS an additive representation of CMYK values using the best approximation available.
So, basically: If you can see it on-screen and you think the colour is right, it's because there is an appropriate RGB value for that colour representation. If those RGB values are restricted to the gamut of your CMYK output, then they will print just fine.
Otherwise it would be impossible to print digital photographs because cameras don't produce CMYK photos, for instance.

Oh, and btw, I've been printing stuff on professional presses for the last 25 years. I think that after thousands of prirt runs and happy customers I can believe I have a slight idea of this.