35 wt thread is probably 3 ply and very thick. Too thick for piecing, it will take up a lot of the 1/4" seam space. Any weight of thread under 50 wt is used if the stitches are to be seen as part of the quilt design. 50 wt and higher wt for stitches that will seem to sink in the quilt. Start with the more expensive quality brands of thread and then compare each brand to others. Soon you will know which brand you are happy with and can look for sales for that brand.