As it sounds like you are aware, printing grayscale images and graduated neutral tones will task a color managed workflow far more than other types of output. I suppose there are two basic ways you can proceed - the right way, or the easy way. Be aware that the easy option will not provide all of the benefits of the right way however.
Option 1:
The 'proper' approach is to have invested time and effort into building and maintaining a properly color-managed workflow. This means accounting for each device in the workflow, and calibrating it at recommended intervals. Printers are typically the most involved, as each time we change print media, we effectively start over, and build a media calibration and profile for that media product, on our own equipment. The media profile procedure includes a linearization of the printer on the media in question. As the device changes over time (new printheads for example), there may be a periodic need to re-linearize the device to get it back into the state that it was in at the point that the original media profile was built.
A properly implemented color managed workflow will allow for all kinds of jobs, including grayscale, spot colors, and RGB and CMYK files, all to be faithfully output on the desired media product.
Option 2:
The 'easy' way is the manner in which most of the sign community works. It involves using 'canned' profiles from whatever source the user can find, print samples and other test prints, adjusting settings, more testing, etc. It can be very wasteful when dealing with demanding clients, be highly stressful, and will rarely if ever generate the best possible result. If this sounds like the approach you take, you are not alone. Roughly 95% of the users go with option 2.
