u/Electronic-One-9935

hey guys! I'm trying to restore a 90s mountain bike at the moment for my partner, but I'm not super experienced and could use some pointing in the right direction!

They have this quill stem adapter that they'd like to use if possible- it screws directly into the fork, but that leaves about 31mm of threading exposed at the top, and obviously with no headset the fork would just drop out if the bike was lifted. i've never used one of these adapters before, so not sure if I'm overthinking, but is there any specific kind of headset that would work best with this?

Thanks guys 💖