Hi, I recently acquired a Toshiba RD-KX50SU HDD/DVD recorder. In the manual it recommends to use "That's (Tayio-Yuden 1x, 4x) discs, and that Panasonic 1x, 4x discs have been tested. Anyone have good luck with any other brands or speeds? If not, where can these specific discs be found for sale? Thanks for your assistance on this.