Giselle

Even a level 17 player can easily take both judgment and clear. The bracket width of the choke point is 152 BPM, so if you're aiming for level 18, you should be able to see it quickly. Personally, I think it's believable even as a high 16. Just a heads-up that the 3-note drops at the end are just horse-riding rhythms.

Seriously, as long as you don't panic during the final section, it's one of the easiest 18s. Even that final part, if you just mash through it somehow, the loss isn't that bad. It feels slightly harder than Queencard, but since there aren't many 18-level patterns in the early or middle sections, if you build up your gauge and just survive the end, you can clear it without much trouble.

It feels slightly harder than the absolute lowest tier?

Just somehow get through the late spike! If you're already touching mid to mid-high 17s, it's definitely worth a try.