A set of sinus balloon catheters are provided for treating a patient's paranasal sinus system, including dilating prepared openings, and natural ostia and ducts and excising sinus cavities. These include a balloon catheter with a bend placing a distal segment at 90° to a proximal segment and a balloon catheter which is substantially straight. The catheters have sufficient stiffness and column strength that the balloon carrying distal segment of the catheter can be pushed into the prepared opening, natural ostium or duct, or sinus to be excised. The catheters have appropriate inflated working diameters and appropriate outer diameters with the balloon deflated that will enable the catheter to be pushed into the respective prepared opening, natural ostium or duct, or sinus cavity to be excised. The methods use the balloon catheters to dilate prepared openings to selected parts of the sinus system, to dilate natural ostia and ducts of the sinus system, and/or to dilate sinus cavities to remove them.