I too went with the connecting threads brand, Essentials. They sell it in lots of different combinations. I had a big problem with the coats and clarks giving my newer bernina fits. My old bernina does not care which thread I use with it. So I will save it for sewing with that one.
The essentials is very reasonable by the collection price.
The color thread is the most important when you are quilting on the top, than when you are piecing. I also use a neutral to my fabric when piecing.
Keep us posted after your class. I really want to see your quilt, it sounds really pretty.