David, I have never tried this and dont know if it will work, but if you can decrease contrast by "bleaching" the latent image with ferrycyanide before you develop, perhaps you can increase it by "toning" the latent image before you develop. Why dont you try selenium toner maybe 1:500 and put the print in the bath before you develop it. Rinse it and then develop it in amidol, and see what happens, and let me know if it worked.