Good advice above. Don't use oily stuff like Minwax stains. Instead use anilines, alcohol or water based dyes. I use alcohol and have dyed lots of lams with no adhesion problems at all.
I too once thought the walnut looked too light after freshly cut and ground, so I stained it with walnut colored alcohol based aniline dye. I just wanted it a little darker, not a lot. I regretted it because after the thing was glued up, it was so dark, I couldn't make out any grain whatsoever. I may just as well have used brown or black glass.