Those Tektro brakes really suck. I tried adjusting them nine ways from November, and they still sucked. Decided rather than mess with different pads to try to and patch it up, I'd look for some good brakes instead.
Last week, I found a set of Ultegra 6600 brakes on ebay, new in box, $52.00 for the set. The difference in stopping power is night and day, and fixed the only glaring shortcoming of a really great bike.