I draw all of my stuff in RGB (because it's going on the internet, of course), but I have printed the first 3 chapters in a collected edition - and what I did was that I used Manga Studio 5/Clip Studio Paint's CMYK-preview function - which lets me know what it's going to look like in print.
You can find that under View>Colour profile (aaaallll the way down at the bottom of the menu) and then clicking "Preview settings". Pick a CMYK profile that fits from the "Profile for preview" dropdown menu. The image you've got open will automatically display as your chosen CMYK-profile, and the colours will change a bit. Bright blues and greens get a bit duller, etc. - but so far there hasn't been any dramatic changes.
Unfortunately, Manga Studio 5/Clip Studio Paint doesn't really give you the option to draw in CMYK, but you're able to export in CMYK if you want - or just use Photoshop to convert files, whichever suits you best.
There are certain colours that you very literally cannot print - certain shades of blue are among them - because RGB uses the light of your monitor to display colour, and CMYK just uses the white of the paper, so neon colours are going to be pretty hard to replicate, but other than that, the difference isn't THAT big.
And if you're printing something, I REALLY recommend that you get a proof-copy from the printer first, so that you can see what it's going to look like in print before you go ahead and get the entire print-run done.