When I use my pfaff to sitd, I engage the idt.
I use the sitd foot. I think it would be hard to do using the 1/4" foot.
As for how much practise, that depends on the user. I make lots of quilts for preemies so I practise on them. The sitd foot makes it easier for me, others will say they don't like it. It's individual reference.
I use the idt for regular piecing,too. I use the idt for everything but some decorative stitches.
When I sitd, sometimes I do other quilting elsewhere, sometimes I just to sitd, it depends on the quilt.