As others have said - the most common spot for a slow hero is either center (if tanky enough) or flank (so they proc) on a d-team.
Exceptions are heroes like Alberich or Mother North where you want them to proc late game, instead of mid-match.
But yeah - Justice is such a pain! Her blind scares me more than Onatel’s special when I’m raiding against her.
As for placement - trial and error is the way. You’ll get all kinds of advice, but I’d just see what works best.
I happen to have Lianna, Rumplestiltskin, and Azlar fully maxed an emblem’d. So who do I put center? None of them are particularly made for center, but I tried each one.
It’s pretty apparent that Rumplestiltskin performs best at center with 720 armor and 1400 hp. By the time he gets pummeled by tiles, he has a 66.666% chance at doing something mean to the enemy (heal/cleanse or burn/dot).
With Azlar flanking him, the lion-boi usually procs without dying. In my heart, I hope enemies flee after getting burn + dot from both of those two lol.
Anyway I’m rambling. Justice is a great hero - I’d put her center if i had her maxed out, because she’s tanky enough to hold the position, and her blind is INFURIATING early in a match, when she’s likely to proc.