So if he send me the ICC of his printer, that would solve my problems? Paper differences aside, of course.
Get him to send you the ICC profile for each of the printing papers that are available on his printing system. He will probably have different profiles for glossy, semi-matte and matte papers. Place these profiles in your profile directory/folder. For example, on a windows system, this will be in:
You can now use these profiles in Photoshop with the "soft proof" feature. Set up the soft proof in the Photoshop menu selection of "View". Choose the "Proof setup" option, then choose "Custom". In this menu, select one of his profiles in the "Device to Simulate" entry box. Ensure that "Preserve CMYK Numbers" is unchecked. Choose a "rendering Intent" of either "Perceptual" or "Relative Colorimetric" (they give slightly different image results), ensure "Black Point Compensation" is checked ON. Usually leave "Simulate Paper Color" and "Simulate Black Ink" unchecked.
When you enable Soft Proof viewing with "CTL/Y" or "Option/Y", you can easily view, on screen, what the image should print like on your commercial printer's system. For final adjustments (usually just curves to make the image darker or lighter), examine the soft proof on the screen and make these adjustments while viewing the proof. If profiles are properly done and you monitor is set for appropriate brightness range, there should be a very good match without any adjustment. Then save the image for shipping to the printer.
There is useful documentation about this in the Photoshop manual as well as tutorials on the Internet.
You might also want to read the book "Color Management for Photographers" by Andrew Rodney (knows as "digitaldog" on this and many other fora). This gives a good description of the color management process in a readable manner with very few things missing.
For what it is worth, I find the best luminance settings of 100 for my monitor is perfect for judging in my working conditions. This level allows me to view the monitor without visual glare. Of course, this is dependent upon the room illumination in which you do your editing. My ambient light is reasonable low at about 50 lux with a colour temperature of 3700K. The room is lit with "cool light fluorescent" bulbs which are rated at 4100K for colour temperature.