i love using bottom line thread---you can get so much more on the bobbin than with the heavier top thread. and it always runs smooth...
i know there are (recommendations) to use the same thread top and bottom- but i (think) that recommendation is usually made when someone is having tension issues- sometimes tension problems can be solved by using the same thread top and bottom
i have never had a tension problem when i am using a (bobbin thread) with a more multi-purpose thread...only when i mix other threads -- like decorative threads/heavier threads.
glad you have found bottom line! it is a great thread!