Indicator for Veigars Ult treshold?

Alot of champions have an indicator for their sure-kill Ult or damage scaling based on missing HP

Evelynn has a similar scaling to Veigar's; if lower than 30% HP damage gets doubled and indicated

Veigar's Ult dmg scales from +0% up to +100% extra dmg based on missing HP, peaking at 2/3 HP missing, except no indicators for this

So here is my idea how it could work: https://cdn.discordapp.com/attachments/324564323118743552/456643685954879499/veigar-indicator.gif