I like doing it all on the longarm....stippling, freehand, stencils but prefer custom because that's what I did when I hand quilted.
You can't ask too many questions!! The one question you don't ask will be the one to come back and bite you in the rear end.
I was comfortable after about the first 6 quilts but that isn't the same with everyone. I never took a class either like most of the people that do this. I haven't been around other quilters. I learned by going to webshots and seeing what other people are doing.