I've downloaded several printer profiles from several labs. They say that their profiles are for soft proofing only. When I use the profiles for soft proofing, I get different results depending on the rendering intent I select as well as whether I choose black point compensation. If the profiles are solely for soft proofing, how do I determine which rendering intent to use and whether I should use black point compensation? I'll try to ask this question of a couple of labs, but maybe someone on this forum already knows the answer.
I soft proof with canned profiles from Epson, etc. and print on my 2200. With each profile, how a soft proof (and pirnt) looks when changing rendering intents and/or BPC depends a lot on the image itself. With some images, the differences in soft proof (and print) when changing rendering intents and/or BPC are minor. These are typically images dominated by pastels without extreme highlights/shadows or saturated colors. But with some other images, the differences can be significant. After a while, I get the hang of what to use with different kinds of images.
When in doubt or with a critical image, I will soft proof with different settings and pick the "best" one to print. Depending on how the print turns out, I may have to iterate the process. And that's just with one profile. Change the profile, and the iterations get even bigger.
If I were to use an outside lab, I would do something similar. I would send the best print to the lab and tell them that's what you want, and how you set the profile's rendering intent and BPC.