[gsparks2]

I installed the plugin you suggested. I am not sure if I have custom columns "built from other columns" but I do have "pages", "Reading List" and "Formats" in my Calibre Library. Retried wireless connection and download of 30 books has taken 14 minutes.

I sort of tested the WiFi speed by comparing internet connection speeds of my PC which has an ethernet connection to the internet and the internet speed of my phone that has a WiFi connection to the internet using the same router device as the PC Ethernet. The download and upload speeds of the two devices are very close to the same, ~12.5 Mbps download and ~2 Mbps upload. I expect the WiFi speed to be much higher than the internet speeds based on what I have read. This test told me nothing of the value my WiFi speed, just that the WiFi speed is not slower than the internet connection speed.