I have a similar workflow, using the Photolinker application mentioned in the original post, with one additional step. I use exiftool to add accuracy data with this command:
exiftool -gpshpositioningerror=10 ~/Pictures/_Import/
This command sets the accuracy of all photos in the designated folder to 10 m, which seems like a reasonable estimate most of the time. in some situations I might use a different value. Unfortunately I have not seen any GPS devices that include accuracy in the GPX files they produce.