I want to calculate a single weighed average (a "Response Index") from three email disposition metrics:

The averages for all campaigns (and thus "Response Index" = 100):
Open Rate 26.3% (a number higher than this is better)
Click Rate 3.4% (a number higher than this is better)
Unsubscribe Rate 0.02% (a number LOWER than this is better)

I would like the "Response Index" to represent these weights:
45% Open Rate
45% Click Rate
10% Unsubscribe Rate

Sample Campaign #1:
Open Rate 20.1%
Click Rate 4.1%
Unsubscribe Rate 0.00%

How would I calculate the Response Index for Sample Campaign 1? This does not work: 20.1%/26.3%*45 + 4.1%/3.4%*45 + 0.00%/0.02%*10

Thanks for your help!!