I purchased the SITD sole for my 440 walking foot. I fell in love with SITD after using it just once! I didn't have to work to make sure I was in the ditch the foot did it for me. When I tried SID without the sole it was not a pretty sight at all. I primarily use SITD to stabilize my quilts before I start quilting. I also have begun using 505 spray exclusively. I've yet to have a problem with the gummy needles and I would say I am rather heavy handed when I spray the edges of the quilt. I do, however, give it a day or more to fully dry before I begin quilting.
I would say, to your question about using SITD foot without the walking foot, the walking foot moves all three layers with just the foot there may be puckering. Even with a good spraying.