Let me describe how I use it, and you can figure out how it can apply to your workflow. Let's say I just got 36 scanned photos from my last roll. I open them all with Preview. If I have a GPS track from that day I will drop it on tracker, which will in turn send it to trackServer and make it appear on Google Earth. If I don't have a track I will just open Earth.

I position Earth at the approximate location where the photo showing at Preview was taken, and run Phototag; if I had a track, the point of the track closest to the center of Earth's display will supply both the geographical coordinates and the time the photo was taken, and no further interaction is required. If I didn't have a track Earth will supply the coordinates (the center of its display) and phototag will ask me the date and time. When done I move to the next photo in Preview, rinse and repeat.

I also find it convenient to delete the obviously bad photos from within Preview with Cmd-Delete. When I am done I import them into Lightroom.

Download, open the disk and copy the three applications to your Applications folder. I find it convenient to add phototag and tracker to my sidebar.

It has three components:

1. Phototag does the tagging. If you drop photos on it they will all be tagged with the same coordinates, but time will be asked for each of them if not already present. If you run without arguments it will tag the photo showing at Preview. If the photo to tag has an xmp:dateTimeOriginal date in the header, as will happen if it comes from a digital camera, the date is not touched. If it does not, the user is asked to supply a date-time value, which defaults to the last one entered (and remembered between sessions). The geolocation comes either from trackServer (see below), or from the point at the center of Google Earth's display.
2. Tracker loads NMEA GPS tracks, and sends them to trackServer. Drop your GPS track on it; it will open trackServer if not already running. Run it without any arguments to close trackServer (below).
3. TrackServer loads the track, displays it in Google Earth, and listens for geolocation and time requests. When one arrives it asks Google Earth for the point at the center of its display, and returns the latitude, longitude and date-time of the nearest point in the GPS track.

I have used icons from the icon archive. The idea on how to ask Earth for its coordinates comes from geotagger. My attempt at explaining how to use Applescript from Python broght in several thoughful comments that made my code better.