I am slooowly putting blocks together today. Sat down with a bluprint class on machine basics, and kept pausing and actually applying the concepts to my machine instead of just going oh I already do that. Turns out I didn't already do that. At least not enough to do it properly. Swapping out to a fresh needle and obsessively rethreading my machine half a dozen times somehow made a difference in how easy it is to get the long seams together. I also found the spot where the triangle seams were catching as the whole block is under the needle, and smoothed it off with tape. And fixed my tension, because my auto-tension apparently does auto-tension properly anymore.
I have one more place where the machine tends to catch right at the beginning of the seams (it actually tore a small hole in a flying geese block yesterday, so that has become a half-block), but I saw something on Bonnie's site where she suggests moving the needle all the way to the right when piecing the flying geese her way because the wide feed dogs on newer machines sometimes distort the tips of the triangles when sewing seams. She also suggested a single hole stitch plate, but I don't have one of those for any of my machines. I will try changing the needle position on the next block and see if it makes it any easier.
I'm getting there....slowly but surely. Definitely happy to be making progress!