My Pfaff takes all types of thread too -- and we probably have different types of Pfaff. I can even use one type on the bobbin and another type on top. No issues.

I think most of the shrink problems in the past came from the fact that we all washed in really hot water. Now, most of us wash things in warm or cool water so the shrinkage is a lot less.

I use both cotton and cotton covered threads. Neither show any adverse effects. I have a quilt from 1973 and still looks like it did when I finished hand quilting it. Everything I have made or make will outlast me and that is all I really care about.