I have the DX7, and use the float function setting with my walking foot when binding my quilts. The setting range is from 0.0 to 2.5 mm. Default setting is 0.5 mm. I usually increase to 1.5 to 2.0 when sewing binding. After turning the binding, I secure it by machine. Works very well for me. I don't do much actual quilting with a walking foot, but I imagine the float function would work just as well for that.
I quilt on my TL2010Q, but always switch to the DX7 for the binding.