Unless it's 203mm rotors you are using be careful, shimano are 160 against the avids 165 and 180 vs 185 so they will leave a bit of the pad on the outside edge not covered by the rotor and will eventually leave a ridge as they wear and the pads will touch together leaving not a lot of braking.
To stop them squeeling, pull the pads out and put a bit of copper slip on the back (non friction material side) and put them back in.