It's definitely easier to hide tension issues if you use the same thread in top and bobbin. It's not necessary, though. Longarmers can mix top and bobbin threads just as domestic machine users do.
However, I am curious about the selection of Sulky rayon for quilting. Rayon thread is not nearly as strong as cotton or polyester thread and I think is not usually used for quilting for that reason. Some time ago I asked here on the QB about using rayon thread to quilt a charity quilt I was finishing up (the thread color was a perfect match), but got quite a few posts that advised against it.