@J. PUPSTER New beta version (same link as previous).
You can split from an existing CUE by using 'Add Cue' button, then 'Split'
You can split from a large FLAC or WAV without a cue by using 'Browse' at bottom to load a auto detect silence. Then 'Split' at any time to use the times in the grid. Although you should add the tracks details via a Musicbrainz tag lookup or manually prior to the split to get nice file names and tags.
Updated to 4.2.6 today and giving this a whirl. Didn't make sense until I came back and read this again. Below I can see my first results with Roberta Flack Side 1 and I'm thrilled to see some tracks. But I'm afraid I'm going to lose these when I switch to side 2. These are split points that I believe to be valid. How do I get tracks to result into that album folder?
Big thanks for these continued improvements!