No experience with vintage machine and WF.
I just finished some boat seat covers using one of their fabrics and the pre-made bias trim. The fabric was black and the trim was a tan one. These were keeping the sun off the regular seats when not in use. I used their # 69 thread in the top thread and for the bobbin. I also used polyester embroidery thread in the bobbin sometimes. My old New Home machine was quite cranky so I used the Dream and managed quite well with it. I'm not sure of the needle type/size. I had to try a few different ones to get the right combination.
Did you see the needle and thread size chart for the different fabrics they offer?
Love the site and helpful information they provide for our DIY projects.