EDIT: Change with some number to make it break even at intended point
so maybe total damage is like quadratic formula rather than linear formula based how long channeled... maybe a good idea to add some counterplay with CC... (less damage at the beginning but if she finished channeling it has more damage)
Live value:
Magic damage per dagger: 35/55/75 (+37.5% bonus AD) (+25% AP)
Max damage per enemy: 350/550/750 (+375% bonus AD) (+250% AP)
maybe to:
Magic damage per dagger: 30/49/68 (+30% bonus AD) (+18% AP)
Increased damage per subsequent daggers: 2/3/4 (+3% AP)
Max damage per enemy: 390/625/860 (+300% bonus AD) (+315% AP)
Since dagger comes per 0.25 seconds enemies have average time at between 0.5 to 1 second needed to react maybe until 4th or 5th dagger comparison to live must be lower:
1st dagger live: 35/55/75 (+37.5% bonus AD) (+25% AP)
1st dagger: 30/49/68 (+30% bonus AD) (+18% AP)
2nd dagger live: 70/110/150 (+75% bonus AD) (+50% AP)
2nd dagger: 62/101/140 (+60% bonus AD) (+39% AP)
3rd dagger live: 105/165/225 (+112.5% bonus AD) (+75% AP)
3rd dagger: 96/156/216 (+90% bonus AD) (+63% AP)
4th dagger live: 140/220/300 (+150% bonus AD) (+100% AP)
4th dagger: 132/214/296 (+120% bonus AD) (+90% AP)
but if they let her finish until final (10th) dagger...
5th dagger: 175/275/375 (+187.5% bonus AD) (+125% AP)
5th dagger: 170/275/380 (+150% bonus AD) (+120% AP)
6th live: 210/330/450 (+225% bonus AD) (+150% AP)
6th: 210/339/468 (+180% bonus AD) (+153% AP)
7th live: 245/385/525 (+262.5% bonus AD) (+175% AP)
7th: 252/406/560 (+210% bonus AD) (+189% AP)
8th live: 280/440/600 (+300% bonus AD) (+200% AP)
8th: 296/476/656 (+240% bonus AD) (+228% AP)
9th live: 315/495/675 (+337.5% bonus AD) (+225% AP)
9th: 342/549/756 (+270% bonus AD) (+270% AP)