Captioning tricks and techniques

I'm working on a large course that has a lot of video.
Captioning is tedious and is taking a long time.

I'm trying to streamline the process by using excel to create vtt files that chunk the captioning into small, approximately 1 second chunks of text spaced every 1.5 seconds. I pull these into the Storyline and then fine tune them with the captions editor, but still find that cumbersome.
Anyone have any awesome tricks to help speed up the process?

Thanks in advance!