Most of my images are edited in the ProPhoto RGB profile. I know this is not the proper gamma, so I have tried to convert to Generic Gray Gamma 2.2 using Photoshops convert function. I always use a step scale on my images for digital negative printing. With Gray Gamma, the values on the scale shift dramatically (70% becomes 62%). If I convert to Adobe RGB, I do not get this shift (the values remain accurate).
What is your recommended workflow for conversion of profiles? Is it fine to just use Adobe RGB?