Ok it's now the "morning after" and I did get some very quality time with the 505 before bed. I'm going to update my original post in this thread with the details.
All who brought this up already are totally right - the super slow font size changing was 100% because I had done a simple file transfer through Windows. All the books I've loaded through the elibrary software were instant font size changes - awesome!
Ok now back up to my original post for the full update.