I am such a bad quilter..I don't prewash anything..well I do but only if I am using muslin as a backing.
If I want a wrinkley look I use Hobbs 80/20, if I want a flatter look I use Dream poly select. This Dream poly feels like cotton and really clings to the tops as I quilt it on my midarm Handyquilter.
I also had a machine that I got from a thrift shop and it came with only one foot...It was a wrong foot and so it sat only one side of the feed dogs.
Then got a featherweight
then two others, one with bells and whistles and my HQ.
Glad you got one that works for you..I have been sewing/quilting for many years but I still learn from this board.