I think this is a fantastic technique for creating a loop with a target length. Copy and paste this region somewhere, add the smallest in and out fades possible, and bounce or export. Now simply highlight the ruler (this does not work with the yellow-box highlight style), hit the “ P” or “ ” keys to move the highlight over the source audio, and playback (making sure you only hear the source audio track). Try to place the starting point of the ruler at a zero-crossing point. As long as the exact length of the original loop is maintained, you can maneuver the ruler to accommodate any large wave forms. Shift it over so that it’s length covers any and all cross-fades in the duplicated source region.
Following the natural pattern of a waveform is especially important if the source material already has a noticeable rhythm to it. Pay attention to the In and Out waveform sizes and try to match them.