With Sound Studio, go to View>Edit Grid and enter grid lines every 588 samples. Then use the 'snap to grid' feature and every marker you drop should be on a sector boundary.
However, it's just as easy to cut wherever you want and then use the 'fix SBE' tab of xACT to encode to FLAC and align on sector boundaries at the same time - that's what I do. Then use the 'shntool' tab to do a 'show len for fileset' or 'show len by disc' to create the track listing and timing for your info file.