@Lunacy-Audio Thanks for that recommendation. It seems like a really really nice solution for when you first sample, but for adapting existing samples, it doesn't seem ideal.

It's an old topic, but seems worthwhile to gather this stuff in a thread.

https://www.bjoernbojahr.de/endlesswav.html
with WINE on a Mac works

Wine is pretty simple to use:
https://www.howtogeek.com/263211/how-to-run-windows-programs-on-a-mac-with-wine/

I wasn't able to get Loop Auditioneer working with WINE - always crashed after I created settings.

+1 for standalone. For example, I really appreciate Arturia providing standalone versions of their synths. It's great for trying things out, using them as "hardware" and building presets. They also do provide a "playlist" feature so it is more friendly to the performer to organize presets for a show.

I have not been able to get a decent crossfade in a basic sample of a waveform. It always seems to "duck" at the loop point. Is there some sort of setting I'm missing for the crossfade?