I've always found that a 7w and 5w are too close in terms of distance. I was told by my fitter a few years ago that I should drop my Yamaha i.f.f 5w 17* in favour of the 7w 20* as I was slightly more consistent with it and not much distance lost. On one occasion my PRGR Egg 9w 22* was actually longer than my Kamui Works Ray 5w 18*. They had the same length shafts.
I would game a 3w/4w at 16* or 17* loft and then a 7w/9w at 20*, 21* or 22* depending on make/model, and as Duffer mentioned, replace a 5i with a high lofted hybrid.
Enjoy.