Rupert - Thanks! My monitor at home is really well calibrated, so pretty much what I see on it is what I can expect to see in my prints (allowing for inherent differences between RGB and CMYK.) So no, I didn’t need to do anything but send my printer the final flat RGB file.
Alwyn - I haven’t ever tried printing on canvas yet. I prefer smooth and slightly rough papers - like watercolor. I don’t feel like my work is brushy enough to work well on canvas!