The hope will need to bed into the disc, this will require lots of riding around with the brake half on, can take quite a while and be quite energy consuming, try not to let the brake over heat though, just short intervals of riding around. People sometimes use water to bed in the disc, not sure what this does though..
Also the fact that you have gone from a 203 rotor to a 160 will make your brake less powerful due to the fact that you have less leverage, if you want more power from your hope then i'd get an adapter (or steal the one off your avid bb7) If your going from a bb7 which is a good brake anyway (203) to a 160 hope then i dear say the power would be worse, only way to find out would be to bed it in. I'd suggest keeping the 203.