I’d suggest 717, 73N, 320 order for best seniority the fastest. 717 will almost certainly lead to better seniority the soonest, but 73N/320 have better pay from year 2 and likely better trip quality. The 320 to 330 career path is very popular now given our aircraft order book, but that seems to be skewing the 320 more and more senior. I tend to prefer the contraction path for better seniority, but YMMV.