Keith's point about the problem of sharing profiles is right on. If you have a good starting point with the ink limit and cross overs for different inks then you can use this spreadsheet tool below for linearizing/correcting to the process and your person variables with the gray-curve line.
It is based on my QTR Correction Curve Tool spreadsheet template I created for linearizing prints to work with digital negatives. I made it a few months ago, and never got around to making a full post about it. I just updated my site with a link to it, but here is a dropbox link to the downloadable file. If you view it on dropbox the formatting and formulas look all weird, so just download it and open it in Excel (Apache Open Office works too but it isn’t pretty).
The spreadsheet tool allows you to measure and enter the print densities, and it will automatically generate a correction curve that you can paste into the Gray\_Curve= line in the ink descriptor file. It solves the problem of fiddling with Photoshop curves and levels adjustments, and still allows you to use the linearization function in QTR to fine tune the final curves or variations in the process. The formulas are hidden and locked down so they won't accidentally get selected/changed/broken so all you need to do is work with the highlighted cells. instructions are pretty simple and are included in the sheet.
When I tested this back in November with Lodima Contact Printing Paper it worked flawlessly with a custom made 5-gray ink profile on the 3800. That profile used 4 partitioned gray inks from the Cone selenium digital negative ink set and a fifth toning ink along the whole range of tones to control any addition density needed or to subtly control the contrast in the negative. I’m testing the P800 with pt/pd this weekend and will see how that goes.
Happy Printing,
Richard Boutwell