On my brother I finally put out for a 1/4 inch foot. It works when I pay attention. When I get a bit lazy it doesn't. Why? you have to push the fabric slightly up against the foot, if you don't it slips away a bit then you get a line that veers or you get too far off the foot you have a lot of trimming. if you push too hard it goes UNDER the foot then you once again do not have a quarter inch and your short. so I use nothing faster than the medium speed, and usually not quiet that fast, and watch what I am doing. Watching sure is easier than ripping a seam or going back and fixing a seam that goes off on its own path. I tried tape not enough but I think maybe tape AND a 1/4 inch foot are not a bad idea at all. that area in front would be lovely to have the fabric simply coming in at that angle and in line. going to go check out bonnie hunters trick.. worth a look for sure. I spent all of last year struggling with my 1/4 seam now is a non issue. ALSO: you can cut your block pieces out a bit larger sew them to the next piece and trim to size perfectly a bit of an extra effort, and a bit more fabric wasted but not much in the large picture. you do get even blocks then with correct seams so you don't lose all the points when sewn together.