I can tell you what I did and maybe that'll help:When I was where you are at I opened classics until I had at least one cover for each of the classic 5-stars (for essential PvE nodes). Then I moved to using all my LTs and CPs exclusively in Latest Legends. That enabled me to fully-cover a couple of 5-stars without hoarding (Black Widow and Spidey; I soft-capped them and didn't champ them right away.) Once I had roughly 75% of the 4-star tier champed and the rest fully-covered, I began my strategy into 5-star play and saved up my 300 pull hoard. That's when I got Okoye and JJ and champed four 5-stars all at once, fully entering 5-star play.