Fantastic Yaks, thanks so much for the feedback, it helps me know that I am speccing these things correctly.
My cartomisers have been a big hit with most of the beta testers, with the LR/LV ones seeming to be the most popular both in and out of the auto-feeders so I am very happy that I specced them to meet the needs of the majority and that the hole size suited most people.
Thanks to all those who took part in this beta test and thanks for the fabulous feedback you all took the time to express, both here and via the PM system. Your help is very much appreciated.