Thank you, I am quilting with a 1916 Singer Redeye mdl 66 and this quilting on the back gives the best look on the top of the quilt. The two threads show up as the handquilting on top of quilt. This is the way I was showed by my grandma and just continued to do the same with this treadle machine. I will try the invisible thread on top and adjust the tension the next time. I have about 40 antique machines including a 1855 Grover and Baker and these machines have thier own way of doing things. I sew with all of them.
PS My wife thinks I am crazy for not using a good electric machine