Fine Tuning The Alignment of External Audio

Using P.E. 14, when I import my video, the audio is, of course, in sync. But I record external audio I can't figure out how to perfectly align the external audio track to the recorder's internal audio track.

1.  I use a clapper to generate a waveform alignment spike on both audio tracks (internal, external)

2.  I import the video with its internal audio track

3.  I import the external video track.

4.  In "expert mode", the external audio only seems to be able to be adjusted in increments of video frames. But unless I get supremely lucky, it's always a touch off.

There must be a way to adjust audio tracks in much finer increments, yes?  Thanks for the assist!

Bodhi