An earth-born Sightstalker's attire that they were formed wearing and height is based on how they feel and what they wish for/want most.
Adeline, when she becomes a sightstalker later into the story, wears a simple gray hoodie, jeans, and tennis shoes, dressing casual as she wants to feel as if she's no different from other people despite who she is. She's 7'9 as she wanted to stick out in the crowd and get more attention than her Dem-eye brother, Isaac (7'2), whilst still being A LOT shorter than Scarf-Sight (8'9) and Bow-Eye (8'11) as she respects them and wants to look up to them.
Scarf-Sight wears a 1 to 1 replica of the scarf her mother gave her, alongside a soft light pink dress with a crop top black hoodie over it, a scrunchy on her wrist, a pair of high heels, and a jingasa, as that was her mother's favorite outfit, as Scarf-Sight misses her so much, idolizes her, and wants to be just like her. She stands at 8'9 as she wanted to stand tall, just like her mother did in her final moments, but she stays 2 inches shorter than Bow-Eye as she wanted to look up at him.
Eye-Way wears a cloak to shroud himself in darkness, as he grew introverted and apathetic to society due to how they manipulated and lied to him again and again, and he wants to be unseen, so when he takes his revenge, they cannot see it coming. He stands at 9'1, the tallest of them all, for he wanted to show the ENTIRE world that every time they tried to knock him down, they only built him up. He wants the guilty to beg for mercy, and he wants the innocent who did nothing but watch as his life fell apart to apologize.
Obsideyean when he first formed wore thin, near useless steel armor as he wanted to tell Bow-Eye that no matter how vulnerable he is, he'll never lose to him, as even after all these years Michael is still just that useless, weak little orphan who can do nothing but cry, just like he always, and how Joshua (Obsideyean) will always overpower him. He stands at 8'11, equal in height, for he wants Bow-Eye to look directly into his eye and accept that he is nothing compared to him. He later formed obsidian armor whilst in tier 11 to show Bow-Eye that no matter what, he'll always get stronger.
And finally...
Bow-Eye wears a simple, sleek tuxedo as a way to show mystery, so his victims will never know what he's about to do. Think about it, a tuxedo can mean many things. It could mean seriousness and professionalism when it's worn by a businessman carrying his briefcase to his office, it could mean sorrow and grief when it's worn by the grieving souls crying in a funeral home, it can mean death, pain, and rot when it's worn by a corpse rotting in their casket, it can mean holiness and rebirth when it's worn by a priest speaking of heaven, it can mean safety and love when it's worn by a groom holding his bride at their wedding, and it can mean prosecution and justice when worn by a lawyer. A tuxedo can mean anything. Tell me, when you see a man in a tuxedo, what do you think? All you can know for sure is that it'll be important, which speaks volumes when you realize that all of those occasions tell Michael's story. Michael's father meant nothing but seriousness and professionalism when he went to work, Michael felt nothing but sorrow and grief when he heard of his father's tragic passing at work, Michael felt pain and rot as he passed, before facing holiness and rebirth as he shook Big Brother Vision's hand, he felt safe and loved as he held Scarf-Sight, his newly wed wife, and then finally, when it was all said and done, he walked with might as he prosecuted the evil, bringing justice to this realm. He stands at 8'11, for he wishes to tower over his victims and watch as they cower, trying to repent, although it is too late.