Curving? You have to guide the fabric a bit, but it should be a case of adjusting the feed dogs? I usually go for original set up too, and in the case of back clamps, as long as I have the basic foot, a feller foot and a zipper I hardly use any of the others. Keep an eye on fleabay or similar places, back clamp accessoires turn up now and then. I would go for oil on model 66, there's no need for grease, it will run a notch or two lighter and smoother on Triflow or Finish Line Ceramic Wet Lube. They are the only ones I have found that might improve on the basic sewing machine oil, which isn't bad at all.