I must not be "getting" it in this thread. All I've done is to create a series in Calibre, use the series number to define the sequence order and then upload to my Reader. The books show up as a Collection in the correct sequence. Just that simple. In other words, I don't use tags to create a series, I just use the series to create a series. I only use tags for genre information.
Here you can see the Mitch Rapp series by Vince Flynn. This shows up in my Sony 600 as a collection titled "Mitch Rapp" with the books listed in the proper sequence. Easy as pie.
Am I missing something?
Brooks