I have done exactly what you are thinking, used Neatsfoot oil and it darkened up the suede, and turned it into the texture of chamois. Here are some pix of the original boot, the stain that wouldn't go away, and the "dye" job with neatsfoot first go, I eventually did the entire boot with neatsfoot and it was very darkView attachment 1205027View attachment 1205028View attachment 1205029. I have since gotten rid of these boots as I replaced them with what I originally wanted. The neatsfoot oil darkened them a lot.
Thank you for the assistance. I will hold off on oiling up my suede chukkas!