I usually tell people that sewing whether piecing or quilting either free motion or stitching with the feed teeth up you have to obey the rules of the road. Always know the speed limit make sure that your vehicle is well tuned and slow down in the curves or to change directions. In this case you may not have to play with the tension if your straight lines are well formed but just need to obey the speed limit in the curves. If you are working on a frame or on a machine where you only drop the feed teeth you can still speed up the needle by changing the stitch length down to a lower number. Your stitches on the front did look a little long. But otherwise I think that you just need a little bit more practice and need to keep a consistent speed on both the hands and the foot pedal.