FWIW, WaveLab already has a good solution for this. In my experience, cutting engineers for vinyl and cassette duplicators strongly prefer 1 file per side instead of a file for each song that must be assembled in some way. This way there is no chance for extra space to be added or things to get out of sequence, and if they use the right software, they can see the WaveLab embedded track markers in the continuous files per side.
In the WaveLab montage, you can use “CD Track Groups” to determine where side A ends and is side B starts (and there is support for double/triple LP etc), and then render a continuous WAV for each side. The bonus is that you can use the Audio CD Report to generate an accurate PQ report for each side so they know where the tracks start and end and these times are accurate for side B and higher because the report for side B and higher starts at 0:00 again just like the file.
This is one of the big reasons I could not use anything besides WaveLab to assemble my masters. So many great features.