I'm just getting started (already watched quite a few of the videos, including the preview-related ones), and converted one of my smaller (<5000 photos) Aperture libraries today to Lightroom to start to understand how Avalanche transforms things. I'm generally pretty happy with things, although there's one or two things I'm finding puzzling. 

It's great that previews are imported (and since I'm still able to run Aperture, I made sure to regenerate full-size previews for any photo with adjustments pre-conversion to ensure they were there.) What makes them a bit less useful is that there doesn't seem to be any association between the previews and the masters they represent in the converted Lightroom catalog. Am I just missing something? It seems like it would be better if they were included in the same projects as the masters, at least, possibly even adding them to the same stacks the masters participate in. 

Entirely possible I'm just missing something obvious here.