Q) How can I tell what spot colours I can produce?
A) If you have a custom ICC profile for your printer, then you can load the profile into Adobe Photoshop and there is an “out of gamut” view that will show you anything in the file that you will not be able to print. Cielab can set this up for you. Another useful tool is the Pantone Bridge book. Previously called “Solid to Process”, this book shows both the true pantone colour, and what is expected from most CMYK printers (you may be able to do more or less than this book shows, but it’s a great way to show your customers what is the expected result if they don’t understand Pantone.