I wind my own bobbins (M) and almost always use the same thread on top. I like Superior, especially So Fine, King Tut (heavier, cotton so more lint) and starting to really like Omni I sometime have problems with Glide--think its me, but I get more loops on back.
I bought used and had taken certification classes at a LQS so I could rent LA time--so basically plunged in. But since I have taken classes from Angela Walters, Jamie Wallen, Dusty Farrell, Kim Bruner, Pat Barry, Sally Terry , DeLoa Jones, and Linda Taylor(and a maintenance class from her husband Rick--definitely suggest a maintenance class!) Learned something from each one of them and highly recommend taking classes at large shows, check out YouTube, Craftsy, and get some books--I turn to Angela Walter's Shapes almost like a reference book.