Thank you for the update Joe!
In regards to the processing time – GeoTIFFs do tend to take longer to process on Avenza side, as it has to essentially break down the file and create all those zoom levels. Geospatial PDFs tend to process faster, but you will sometimes sacrifice the resolution when using them (again depending on settings, etc.)
I’m glad you were able to find that threshold and are happy with it! As always if you come across any other problems or questions please don’t hesitate to reach out to us through support.avenzamaps.com/hc